Help: Sluggish acceleration

**mmadlang** · 08-22-2011 05:01 PM

Hi all, I need your help. I have a Audi 2007 2.0T CVT with 106K on it. Check engine is OFF, but the car is not as responsive as it used to. Even comparing to other cars that I drove lately, this car is just sluggish. When I say sluggish, I need to step on the gas pedal more to accelerate.

Sometimes, the car jerks from full stop to when I hit the gas pedal, especially during the morning. After than, driving seems normal, except for sluggish acceleration as noted below.
Sluggish acceleration
There's a little bit hesitation when switching from park mode.
NO rough idle
NO stuttering
PCV has been replaced
Cam follower has been replaced
NO check engine light

Thanks!

**seal66** · 08-22-2011 05:29 PM

I don't know if this helps,

but I was experiencing, so lag off the line and between certain RPM ranges. This was even after I installed my test pipe. I just installed my Rev D DV and it fixed everything.

**dumpedb5** · 08-22-2011 05:49 PM

probably just heat soak. Audi's don't like warm weather.

**ceochoi** · 08-22-2011 06:10 PM

Having same problem here.

**CorneliusRox** · 08-23-2011 07:41 AM

definitely interested.

**makav3li** · 08-23-2011 08:13 AM

Are you tuned? Any performance mods? I'd put my money on the diverter valve. Or it could be carbon buildup at that amount of miles but you usually have the CEL flash at you saying there are misfires.

**groundround** · 08-23-2011 08:15 AM

I just hit 109 and started getting check engine light after all the slugish feeling. I had the carbon scraped off and feels like new. $525 at dealer, I recommend it to anyone

**fordyoz** · 08-25-2011 07:31 AM

I am having the carbon cleaned up as we speak. About $500 charge also. Should restore some power (im at ~82k miles)

**mmadlang** · 08-25-2011 07:58 AM

Originally Posted by makav3li

Are you tuned? Any performance mods? I'd put my money on the diverter valve. Or it could be carbon buildup at that amount of miles but you usually have the CEL flash at you saying there are misfires.

Not sure what you mean by tuned, but I have stock parts; no performance mods. Do you still think it might be the diverter valve?

Thanks!

**mmadlang** · 08-25-2011 08:01 AM

Originally Posted by fordyoz

I am having the carbon cleaned up as we speak. About $500 charge also. Should restore some power (im at ~82k miles)

Hmmm.... Thanks for the input Fordyoz and Groundround. From reading different forums about engine sludge, this might be worth it. I tried sea Auto-RX a few months, but didn't really help for me.

**fordyoz** · 08-25-2011 08:47 AM

Yea - I dropped off my car at a local audi/vw performance shop for some other work and asked if they had any suggestions for restoring/gaining power - they said they found significant carbon buildup, and cleaning it would noticeably restore lost power.

**mmadlang** · 08-25-2011 09:25 AM

Originally Posted by fordyoz

Yea - I dropped off my car at a local audi/vw performance shop for some other work and asked if they had any suggestions for restoring/gaining power - they said they found significant carbon buildup, and cleaning it would noticeably restore lost power.

Interesting, let me know if it helped.

**fordyoz** · 08-25-2011 10:46 AM

Originally Posted by mmadlang

Interesting, let me know if it helped.

will do. I wont have it back until Wednesday though :(

**papadelogan** · 08-25-2011 12:22 PM

Originally Posted by seal66

... I just installed my Rev D DV and it fixed everything.

I bought an 05.5 B7 A4 2.0T quattro and replaced the DV with the latest version Rev D and it made a nice difference.

Originally Posted by dumpedb5

probably just heat soak. Audi's don't like warm weather.

It's been over 90° here for several days and she's been a little "off". I picked up some Denso plugs since I don't know when the last tuneup was. May help, may not, but at least I'll know how fresh my plugs are...

**mmadlang** · 08-26-2011 07:12 AM

UPDATE:

I changed my Fuel Filter, and my car feels a little bit better. It's not too sluggish anymore. I feel it's a tad bit not responsive, but maybe this time it's just me... :) Anyway, it's a very cheap and EASY fix.

I think I can gain more performance after putting Seafoam.

Thanks for all your feedbacks!

**Hugh@EuropaParts** · 08-26-2011 07:55 AM

Hey guys... I have experienced the same thing on more then one occasion. Here are some things that were causing my "sluggishness".

1) Broken diverter valve. If you're not holding boost, obviously the car will feel sluggish.
2) Heat soak. This should be self explanatory. However for those you are unfamiliar here is an explanation;
Heat from the hot side of the turbo transfers to the cold side of the turbo (or the head itself can heatsoak as well). This increases the Charge Air temps from the Turbo/supercharger (Charge Air Temp = Ambient Temp+ Cold Side Temp + Compressed Air Temp, we normally assume Cold Side Temp = Ambient Temp). When you heat soak to the cold side, you have effectively created a turbo operating in a heater, this creates lower density > higher charge air temps pre/post IC. This is also a natural phenomenon, when cold and hot side temp differentials get large enough. Water and oil in the bearing housing absorb this in normal boost and driving conditions.
Heat soak obviously occurs more in the summer.
3)Driving habits. Our computers "learn" the way we drive. If you have been using cruise control/a.c. during the summer, the computer learns that driving habit. Best way to clear this up is by resetting the throttle body;

key in ignition
press gas pedal
turn ignition to "aux" (do not turn car on)
wait 10 seconds
take foot off pedal
remove key

OR, you can just jump on the nearest highway and floor it!!!

If any of those don't work, I would highly recommend;
Ultimate Service Kit (A4 B7 2.0T)

**papadelogan** · 08-26-2011 08:28 AM

I put new plugs in last night (Denso PK20PR11 Double Platinum) and she's running smoother today. Probably time for a fuel filter as well.... gotta love buying used!

**CorneliusRox** · 08-26-2011 08:43 AM

I swore I read that our fuel filters are 'lifetime filters'. Obviously that doesnt make sense because junk clogs up on it, but what kind of mileage are we talking about for one?

**mmadlang** · 08-26-2011 08:59 AM

Originally Posted by CorneliusRox

I swore I read that our fuel filters are 'lifetime filters'. Obviously that doesnt make sense because junk clogs up on it, but what kind of mileage are we talking about for one?

Bentley manual states "Fuel filters do not have a specific replacement interval but should be replaced as conditions or situations dictate." I read somewhere change every 40k, I think it's a little bit aggressive. I just replaced mine after 106K.

**mmadlang** · 08-26-2011 09:01 AM

Thanks tip # 3!

Originally Posted by Hugh@EuropaParts

Hey guys... I have experienced the same thing on more then one occasion. Here are some things that were causing my "sluggishness".

1) Broken diverter valve. If you're not holding boost, obviously the car will feel sluggish.
2) Heat soak. This should be self explanatory. However for those you are unfamiliar here is an explanation;
Heat from the hot side of the turbo transfers to the cold side of the turbo (or the head itself can heatsoak as well). This increases the Charge Air temps from the Turbo/supercharger (Charge Air Temp = Ambient Temp+ Cold Side Temp + Compressed Air Temp, we normally assume Cold Side Temp = Ambient Temp). When you heat soak to the cold side, you have effectively created a turbo operating in a heater, this creates lower density > higher charge air temps pre/post IC. This is also a natural phenomenon, when cold and hot side temp differentials get large enough. Water and oil in the bearing housing absorb this in normal boost and driving conditions.
Heat soak obviously occurs more in the summer.
3)Driving habits. Our computers "learn" the way we drive. If you have been using cruise control/a.c. during the summer, the computer learns that driving habit. Best way to clear this up is by resetting the throttle body;

key in ignition
press gas pedal
turn ignition to "aux" (do not turn car on)
wait 10 seconds
take foot off pedal
remove key

OR, you can just jump on the nearest highway and floor it!!!

If any of those don't work, I would highly recommend;
Ultimate Service Kit (A4 B7 2.0T)

**delslo323** · 08-26-2011 09:41 AM

Originally Posted by mmadlang

Sometimes, the car jerks from full stop to when I hit the gas pedal, especially during the morning. After than, driving seems normal, except for sluggish acceleration as noted below.
Sluggish acceleration
There's a little bit hesitation when switching from park mode.

I'm not really sure on common problems for the CVT but it could also be your tranny. at 100k+ miles you might need to change out the fluid for your tranny? Especially if it seems like there's that hesitation from park to drive, this is the one that makes me suspect it is your transmission over anything else.

**Hugh@EuropaParts** · 08-26-2011 09:54 AM

Originally Posted by mmadlang

Thanks tip # 3!

I freaked out myself until I realized this was the cause of my "sluggishness".

**CorneliusRox** · 08-26-2011 01:22 PM

thanks!

**mmadlang** · 09-01-2011 07:57 AM

UPDATE:

After replacing the diverter valve with revision "D". My car's performance improved. The growling noise that I hear during sudden release of the gas pedal that I thought was a bad right rear wheel bearing was gone.

My car still jerks in the morning when I press on the gas pedal the first few times, and there still some slight hesitation switching it from Park to Drive. As mentioned above, I think this is a separate issue, and my car needs a ATF replacement.

I'm confident the sluggish issue of my car has been resolved.

Summary:

Replaced fuel filter
Reduced carbon build up by using Seafoam
Replaced Diverter Valve with revision "D"

**CorneliusRox** · 09-01-2011 08:20 AM

Originally Posted by mmadlang

UPDATE:

After replacing the diverter valve with revision "D". My car's performance improved. The growling noise that I hear during sudden release of the gas pedal that I thought was a bad right rear wheel bearing was gone.

My car still jerks in the morning when I press on the gas pedal the first few times, and there still some slight hesitation switching it from Park to Drive. As mentioned above, I think this is a separate issue, and my car needs a ATF replacement.

I'm confident the sluggish issue of my car has been resolved.

Summary:

Replaced fuel filter
Reduced carbon build up by using Seafoam
Replaced Diverter Valve with revision "D"

Congrats dude! BTW I get that kinda shaky gas pedal in the morning. I just seafoamed, oil change, and I will be doing plugs and an intake filter soon. I'll let you know if that helps

**fordyoz** · 09-01-2011 07:03 PM

well the carbon cleanup didnt improve performance noticeably...will post before and after pics shortly

BEFORE

AFTER

**papadelogan** · 09-01-2011 08:11 PM

It definitely looks better, but if there's no real improvement, that's disappointing. I wonder if your wastegate needs adjusting? Mine probably does, but I haven't had time to do some testing for that yet. I need to reset my throttle with the info Hugh shared above. Thanks for that Hugh!

**CorneliusRox** · 09-02-2011 08:46 AM

you should have let some seafoam or something sit in there (if the valves were seated) and break it up a bit too. I bet it really would have worked with all the scratches exposing it.

**fordyoz** · 09-05-2011 05:39 AM

Originally Posted by CorneliusRox

you should have let some seafoam or something sit in there (if the valves were seated) and break it up a bit too. I bet it really would have worked with all the scratches exposing it.

\
i didnt do the carbon cleaning myself...and i dont know anything about seafoam. is it something i can easily do on my own?

**blakeow14** · 09-07-2011 05:21 PM

Originally Posted by fordyoz

\
i didnt do the carbon cleaning myself...and i dont know anything about seafoam. is it something i can easily do on my own?

x2

**mr shickadance** · 09-07-2011 07:18 PM

Originally Posted by mmadlang

Hi all, I need your help. I have a Audi 2007 2.0T CVT with 106K on it. Check engine is OFF, but the car is not as responsive as it used to. Even comparing to other cars that I drove lately, this car is just sluggish. When I say sluggish, I need to step on the gas pedal more to accelerate.

Sometimes, the car jerks from full stop to when I hit the gas pedal, especially during the morning. After than, driving seems normal, except for sluggish acceleration as noted below. (its cold....all cars are a bit tempermental when they are cold)
Sluggish acceleration (DV valve)
There's a little bit hesitation when switching from park mode. (could just be since you noticed things been slower then usual you are TRYING to find little things that you think are wrong, but may in fact have been there the whole time)
NO rough idle (DV valve)
NO stuttering (DV valve)
PCV has been replaced
Cam follower has been replaced
NO check engine light (dv valve)

Thanks!

as you can tell, i think your problem lies in the DV valve..... could just be a simple boost leak which will show a decrease in performance all while making the car seem ok and not throw and CEL lights

ANOTHER NOTE:

your car has a ton of fucking miles on it.....your car has a glas transmission (i am not beating on the fact that he has an auto, that is his choice and i can respect it if you can) however, you cannot ignore the fact that CVT's with greater then 100k on the odometer generally have an expensive repair coming their way sooner or later. not trying to tell you what to do, but if i was in your shoes i would start to think about trading her in while her transmission is not in pieces. this has nothing to do with driver skill or anything like that, audi's CVT for our cars do not really handle our strong torque (even out of the factory no chip)

all im saying is give it a little thought

**CorneliusRox** · 09-08-2011 07:03 AM

Originally Posted by fordyoz

\
i didnt do the carbon cleaning myself...and i dont know anything about seafoam. is it something i can easily do on my own?

It basically just eats up carbon. So you could pour a bit on there and let it sit and it would lift a bunch of it off. Look on search and you can find some how to's for seafoaming your car. I did mine when I got it and it actually smoked very very little which usually means there is very little carbon build up, but some guys fill a parking lot with gross smoke. You can put it in your gas tank, oil, and vacuum tube. It works great for the price, but definitely not as well as a 'head off' steaming.

**80sGuy** · 12-26-2011 07:12 PM

Originally Posted by mmadlang

UPDATE:

After replacing the diverter valve with revision "D". My car's performance improved. The growling noise that I hear during sudden release of the gas pedal that I thought was a bad right rear wheel bearing was gone.

My car still jerks in the morning when I press on the gas pedal the first few times, and there still some slight hesitation switching it from Park to Drive. As mentioned above, I think this is a separate issue, and my car needs a ATF replacement.

I'm confident the sluggish issue of my car has been resolved.

Summary:

Replaced fuel filter
Reduced carbon build up by using Seafoam
Replaced Diverter Valve with revision "D"

Okay reviving old thread here...
Dude, I am having the same problem as you described from your first post. I'm currently at 26,700 miles and had recently went in Audi service for a PCV replacement under warranty. It helped the erratic idling but I am somewhat losing boost, especially during opening throttle from a dead stop (not wot) and this growling/groaning/moaning noise like you mentioned comes on when the tach reaches to about 2000rpm...talk about S-l-u-g-g-i-s-h...felt like I was towing the Titanic! But it seemed fine if I go easy on the accelerator. The jerkiness you're talking about is probably normal for the CVT, I remembered having this issue when I bought the car new, and like all else you've mentioned; smooth idling, no rough idling, and no cel.
I ordered the revision 'D' Valve and the N80 Purge Valve from Europa (the N80 should help with the jerkiness from a stop) and we'll see how it goes. From reading this thread I am almost 99.999% certain that the DV is the culprit to my problem...or at least I can hope for at this point.

**saucyzest** · 03-13-2012 09:04 AM

Originally Posted by 80sGuy

Okay reviving old thread here...
Dude, I am having the same problem as you described from your first post. I'm currently at 26,700 miles and had recently went in Audi service for a PCV replacement under warranty. It helped the erratic idling but I am somewhat losing boost, especially during opening throttle from a dead stop (not wot) and this growling/groaning/moaning noise like you mentioned comes on when the tach reaches to about 2000rpm...talk about S-l-u-g-g-i-s-h...felt like I was towing the Titanic! But it seemed fine if I go easy on the accelerator. The jerkiness you're talking about is probably normal for the CVT, I remembered having this issue when I bought the car new, and like all else you've mentioned; smooth idling, no rough idling, and no cel.
I ordered the revision 'D' Valve and the N80 Purge Valve from Europa (the N80 should help with the jerkiness from a stop) and we'll see how it goes. From reading this thread I am almost 99.999% certain that the DV is the culprit to my problem...or at least I can hope for at this point.

Any update on this? I also had my PCV done by the dealer - I think you were helping me on another thread RE pcv part#....anyway I have the EXACT same symptoms.

The PCV got rid of my CEL but things still aren't the same. Also did my 55k maintenance (plugs, air filter, oil, etc) and it's definitely smoother at idle but still have erratic and unpredictable acceleration from dead or slightly rolling stop. Sometimes its fine, others it drags quite a bit per your titanic example. Very strange.

**80sGuy** · 03-13-2012 02:29 PM

^^Saucyzest, I'm still experiencing the same problem only not as bad as before. So far, these are the list of things that was done/serviced:

*PCV (P)
*Breather Tube (A)
*DV (D)
*N80 Purge Valve
*Oil change
*Transmission Fluid change (CVT)
*Air Filter

While replacing the Air Filter, I've also cleaned out a bunch of leaves from the 'snow screen' filter and the car idles a bit better. The 'boost' is still there but somewhat a little 'lost' during low-end. Overall, it is not as responsive as it used to be and I felt like I've lost it forever. I'm nearing 30,000 miles and here's a list of things I'm looking forward to do:

*New Spark Plugs
*Ignition Coils

...and one other mystery thing which I will update later.

**Charles.waite** · 03-13-2012 03:03 PM

Here's a total shot in the dark, but a failing alternator could, possibly, cause not enough current to be sent to the coilpacks causing misfire like symptoms. I might be totally off base, but weak batteries can cause all sorts of weird issues...

Could it be a bad N75 or wastegate? I know you've been trying to fix this issue for quite some time, so I'm sort of just spitballing...

**80sGuy** · 03-13-2012 03:29 PM

The N75 was lingering in my mind for the longest time. The only reason why I skipped it was because of the low mileage, but again I'm being biased for replacing the N80...maybe I did it because it was easier to reach. When I glanced at the tight gorge between the radiator and the motor, I knew there was no way I'd be able to squeeze my hand in there unless I hoist the car up high and go from underneath.

**Charles.waite** · 03-13-2012 03:38 PM

Originally Posted by 80sGuy

The N75 was lingering in my mind for the longest time. The only reason why I skipped it was because of the low mileage, but again I'm being biased for replacing the N80...maybe I did it because it was easier to reach. When I glanced at the tight gorge between the radiator and the motor, I knew there was no way I'd be able to squeeze my hand in there unless I hoist the car up high and go from underneath.

Audi's engine bays are not designed for those of us with caveman hands. I've had a replacement DV for my 1.8t sitting in my shed for close to 3 months. I haven't installed it because I'm lazy and you can't access it from the top, lol...

Well, that and my PCV stuff (1.8t not 2.0t) is all held together with zipties right now

**80sGuy** · 03-13-2012 03:46 PM

Oh man, I tried the DV and IT WASN'T FUN! 45 minutes later I ended up putting the bottom plastic cover back, unjack the car down and head straight out to my local (non Audi) mechanic and paid him $25 to hoist the car up, then instructed one of his mechanics of how to replace it. I might do the same for the N75 in the near future.