Cylinder Misfire Detected P0300, swapped in new coil packs, no difference, what next?

[drewgold]

Had a really weird thing happen tonight, I had backed my car out of the driveway this afternoon to get another car out of the garage. Then pulled my car back into the driveway. All seemed good.

I jumped in my car tonight and almost immediately the car started running really rough, making a terrible noise, like a whak, chug, chug, chug

It is obviously misfiring and the codes below support that so I was hoping it was just a bad coil, replaced all the coils with a spare set I have and tried starting it, again, the engine is running rough as before. No change with the new coils.

It seems to be much more of a violent misfire than when coils have failed in the past and it definitely made a very bad noise right after idling rough for a few seconds and right before throwing codes.

Thoughts? What's the process to check diagnose the misfires? Plugs are only about a month old. I'll pull them tomorrow to check but doubt it's plugs. Seem to have ruled out coils, what's next to check?

3 Faults Found:

000768 - Random/Multiple Cylinder Misfire Detected
P0300 - 001 - - MIL ON
Freeze Frame:
Fault Status: 11100001
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 153918 km
Time Indication: 0

Freeze Frame:
RPM: 1560 /min
Load: 42.3 %
Speed: 0.0 km/h
Temperature: -7.0°C
Temperature: -8.0°C
Absolute Pres.: 860.0 mbar
Voltage: 14.351 V

000771 - Cylinder 3
P0303 - 001 - Misfire Detected - MIL ON
Freeze Frame:
Fault Status: 11100001
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 153918 km
Time Indication: 0

Freeze Frame:
RPM: 880 /min
Load: 51.7 %
Speed: 0.0 km/h
Temperature: 0.0°C
Temperature: -8.0°C
Absolute Pres.: 860.0 mbar
Voltage: 13.970 V

000772 - Cylinder 4
P0304 - 001 - Misfire Detected
Freeze Frame:
Fault Status: 01100001
Fault Priority: 0
Fault Frequency: 1
Reset counter: 255
Mileage: 153918 km
Time Indication: 0

Freeze Frame:
RPM: 2573 /min
Load: 58.0 %
Speed: 0.0 km/h
Temperature: 3.0°C
Temperature: -8.0°C
Absolute Pres.: 850.0 mbar
Voltage: 13.970 V


Readiness: 0000 0000

[B44]

Check and clean maf or replace if defective. Check pcv connection to intake manifold.

[audihere06]

Seems odd that two would go at the same time but pull the plugs and inspect and check gap first. Did plugs on my cousins car and one of them was barely gapped wrong and was misfiring like hell.

[drumnjuny]

yup, check plugs and gap, after that my best suggestion is check for a boost leak in the intercooler piping, after that take logs with VCDS and see if your lambda is all wacky, maybe your wideband is shot... have you checked your cam follower recently? definitely check that...

how many miles / what year? the more info you can give us, the better!

[drewgold]

Ok, thanks for the replies.

Some more info:

I'll try and run home and pull the plugs on my lunch break (I can't drive the car given how bad the missfires are). The plugs are only a month old and were gapped to 0.028 so I expect that they're fine. I'll double check to be sure.

I had a massive cam follower failure a few months ago. The cam, HPFP, follower and entire cylinder head assembly was replaced by the dealer under warranty. The PCV valve and IRMC were also replaced. There's about 2500kms on the new follower. Haven't checked it but safe to assume it's ok?

I have 150,000kms (93,206 miles) on the car. Its a 2006 2.0t Manual Quattro Avant.

I will check the intercooler piping but wouldn't that create misfires under higher RPMs /load?
My issue is severe misfires at idle.

[audihere06]

Maybe a vacuum leak.


Sent from my iPhone using Tapatalk

[SwiftA4]

I agree with everyone. Double check everything ....

I will state this, and this is 100% probably not your case, but in the event you check everything and it is all fine there may be a more serious problem.

Not to long ago, i was dealing with some very violent misfires. I originally thought that the coil packs went bad, replaced them with spares just like you, and it was still violent. Turned out i snapped a valve spring in half on cylinder 1 causing the valve to stay open (Thankfully). That cylinder had 0psi of compression.

Most likey it is going to be something alot smaller and easier than what i dealt with, but if all else fails and everything checks out, try running a compression test to rule out those possibilities.

[Jake@JHM]

Plugs, gap, vacuum leak, etc..

Is there water in those coil pack tunnels?

[kegobeer]

try running a compression test to rule out those possibilities.

It's easy and costs nothing to do (borrow/rent the tool from Autozone), so IMHO the OP should just do the compression test to rule out any cylinder issues.

[drewgold]

Just going into a meeting so will update more in a bit but pulled plugs on lunch hour and all four were jet black. (Pics to come) The two cylinders that were misfiring had the plugs covered in gasoline too.

Swapped in spare plugs I had and car started no problem, no misfires.

So seems like I'm running either rich or lean, can't remember which is which with black carbon covered spark plugs.

Thoughts?

More to come.

[SwiftA4]

http://www.audizine.com/forum/showth...ent-Guide-v2-0

[drumnjuny]

^^ one of the first threads that i learned a shit ton from

[drewgold]

Thanks for posting that link, I know I had seen that somewhere before but didn't have time to look it up.
Here's one of my plugs. Quite obviously serious carbon fouling, it was the same on all four cylinders:



Question is now, what's causing the carbon buildup?
These plugs are only 2 months old. They are NGK coppers BKR7E

I have never had carbon issues in the past, is there a chance something went wrong with the cylinder head replacement?

The three causes listed in the spark plug guide that apply for my situation are:
Faulty choke - over rich air/fuel mixture (Could this be cause by a vac leak?)
Delayed ignition timing
Bad ignition leads

Where should I start looking? Or should I be taking the car back into the dealer who did the engine work? Seems very strange that this has only happened since they replaced the head.

[Jake@JHM]

^^ one of the first threads that i learned a shit ton from

Lol, the original information in that thread was completely wrong and everyone was using the incorrect heat ranges (even shops were selling the wrong spark plugs). Wasn't until I put up a fuss that it got fixed which is why its now Version 2.

[drewgold]

Well thanks for being on the ball! It's a great guide. I have certainly used it in the past. I assume much of the confusion stemmed from the reversed scales between NGK and Bosch?

Lol, the original information in that thread was completely wrong and everyone was using the incorrect heat ranges (even shops were selling the wrong spark plugs). Wasn't until I put up a fuss that it got fixed which is why its now Version 2.

[Jake@JHM]

Well thanks for being on the ball! It's a great guide. I have certainly used it in the past. I assume much of the confusion stemmed from the reversed scales between NGK and Bosch?

No prob! The reverse scaled aspect was okay, but the information was identical to the lower compression 1.8T engine spark plug recommendations. So every recommended plug was 1 step hotter than it should have been.


Higher compression engines need colder plugs than lower compression engines because the increased compression creates more heat so you need a colder plug that can pull the residual heat out of the cylinder.


For reference, these are the plugs I highly recommend for tuned 2.0Ts

https://jhmotorsports.com/shop/catal...27t-p-686.html

[drewgold]

Opinions on where I go from here?

My car is an 06 A4 Avant, 2.0tQ Manual, no engine mods.

The plugs have less than 2000kms on them and are NGK BKR7E coppers.

No other codes were found, no rich code, no nothing.
Ideas on what's causing this?

As mentioned above, I had my cylinder head replaced after a massive cam follower failure and wondering if the problem is related? I had no carbon buildup issues previous to the cylinder head replacement, in fact when I pulled the old plugs right after the replacement, they looked to be in excellent condition.

How likely is it that this is related to the cam follower failure and cylinder head replacement?

Also looking for suggestions on where/how to start troubleshooting? Is a compression test still relevant? There is nowhere locally that rents compression testing equipment so I'd have to pay a shop to do it.

O2 sensors? Check for vac leaks? What else could cause such bad carbon buildup in such a short amount of time?

[drumnjuny]

Lol, the original information in that thread was completely wrong and everyone was using the incorrect heat ranges (even shops were selling the wrong spark plugs). Wasn't until I put up a fuss that it got fixed which is why its now Version 2.

haha oh really?? damn i'll have to check it out again!!

[audinutt]

Moving cold cars causes these type of issues too. Btdt start cold car is running rich back out Park it. Then let it sit and restart... Now plugs get fouled.

Sent from my SCH-I605 using Tapatalk 4

[Jake@JHM]

Opinions on where I go from here?

My car is an 06 A4 Avant, 2.0tQ Manual, no engine mods.

The plugs have less than 2000kms on them and are NGK BKR7E coppers.

No other codes were found, no rich code, no nothing.
Ideas on what's causing this?

As mentioned above, I had my cylinder head replaced after a massive cam follower failure and wondering if the problem is related? I had no carbon buildup issues previous to the cylinder head replacement, in fact when I pulled the old plugs right after the replacement, they looked to be in excellent condition.

How likely is it that this is related to the cam follower failure and cylinder head replacement?

Also looking for suggestions on where/how to start troubleshooting? Is a compression test still relevant? There is nowhere locally that rents compression testing equipment so I'd have to pay a shop to do it.

O2 sensors? Check for vac leaks? What else could cause such bad carbon buildup in such a short amount of time?

I think it is time for the full JHM Treatment. Go JHM everything and you will enjoy your Avant on a whole new level

[drewgold]

Haha, I think you're right, however all of these issues are really cutting into the time I have to start modding! So far my car has spent almost as much time broken in my driveway and in the shop as it has on the road. Definitely need to get all the gremlins sorted before I take the mod route!

I think it is time for the full JHM Treatment. Go JHM everything and you will enjoy your Avant on a whole new level

[drewgold]

Moving cold cars causes these type of issues too. Btdt start cold car is running rich back out Park it. Then let it sit and restart... Now plugs get fouled.

Sent from my SCH-I605 using Tapatalk 4

Seems like what happened in my case but worried that it's a sign of another issue.

Also wondering if running a warmer plug for the winter would help? Maybe a NGK BKR6E? May help burn off the carbon.

[Jake@JHM]

Haha, I think you're right, however all of these issues are really cutting into the time I have to start modding! So far my car has spent almost as much time broken in my driveway and in the shop as it has on the road. Definitely need to get all the gremlins sorted before I take the mod route!

Nonsense! The mods will help you figure out what is bad much faster!

[drumnjuny]

^^ that's actually true. it will push any failING components to rear their ugly head before they cause any major issues therefore helping you with preventative maintenance!!