Random Misfire during idle and ignition

**adamleaf8601** · 03-25-2018 09:35 PM

I have a 2009 Audi A4 2.0t that is plagued with a random misfire code. The car mainly misfires when it is idling, or during ignition. I have already put in new ignition coils, coil connectors, high pressure fuel pump, alternator, pcv valve and spark plugs. I have also done carbon cleaning. The car is stock and has no modifications.

Does anyone have any thoughts or ideas as to why the car is still misfiring?

**casey_tuzziano** · 03-25-2018 11:22 PM

Do you see any oil leaking in between the engine and transmission?

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**flowhigh** · 03-25-2018 11:26 PM

The 2.0T will misfire at cold start to begin with. Carbon cleaning rules out that unless it was like 30K miles ago.

Misfires are as fundamentally simple as air, fuel and spark as they say, but these can go outta wack for a plethora of reasons. You or someone with vagcom has to do some serious logging. I could tell you to something like "do a compression test" and that would just be a start in only one of many directions.

**adamleaf8601** · 03-26-2018 07:09 AM

Sometimes I do see some oil leaking, yes.

**TJet1.8** · 03-26-2018 07:20 AM

I had the same type of issues with my A4 (2011) and the wife's A4 (2012).

As mentioned above, there could be a plethora of reasons for the misfires.
What seemed to work (for me) were to replace the following:

1.) Coilpacks
2.) Sparkplugs
3.) MAF

The wife's A4 (78,000Km's) smoothed right out after replacing the above.
My A4 (97,000Km's) got better...but wasn't quite perfect.

Now...I had the Stage 2 Piston/Rings replaced on my A4 under warranty AS WELL AS a new Timing Chain/Tensioner/Guides at the same time.
Once that was done...it was like a new car off the lot. She was smooth as butter.

GL.

**adamleaf8601** · 03-26-2018 12:32 PM

I had my mechanic look at it today and he said that all the spark plugs were loose and that could be the reason for the random misfire. We removed them and put them back correctly and the misfire persisted. I went back to the shop for further diagnosis; my mechanic scanned the car live and found that cylinders 1 and 3 were the only ones misfiring. We swapped the spark plugs to cylinders 2 and 4 to try and determine if the spark plugs are the problem. My fear is that the timing chain has skipped a couple teeth. Anybody have any further thoughts?

**adamleaf8601** · 03-26-2018 09:37 PM

Any thoughts?

**flowhigh** · 03-26-2018 11:25 PM

So the misfires stayed on 1&3 after you swapped the plugs, yes?

You swapped the old with new VW/Audi coil packs, yes?

How long ago was the carbon clean?

Don't know your mec's prowess, but he should've been able to tell if there was a timing issue if he had a capable scanner.

Some things I'd do is look at the injection IQ, injection quantity or injection quotient depend on who you talk to. I'd to this just to get a clue on how the injectors are doing. Ever try a couple of cycles of fuel system cleaner?

Mentioned a compression check, this could easily be done. I doubt this would be the issue though unless your engine had bad history or you like to beat on it.

I'd check fuel pressures, both the high and low sides.

I'd even borescope at least one of the intakes ports.

Honestly, you'd be better to find a really experienced independent Audi mechanic and get his opinion after his diagnostic.

Could be something really obscure and simple. But without taking some in-depth looking it's really hard to pin without more info. Get that oil leak looked at too.

So you just have the misfire codes?

**TJet1.8** · 03-27-2018 05:57 AM

Oh...forgot 1 thing...

I also ran 2 tanks of gas with fuel injector cleaner.
Then...took them on the highway for an Italian Tune up

(Hey...I'm Italian, eh oh...oh eh...)

**Jezza** · 03-27-2018 06:32 AM

Try reducing the spark plug gap and/or running an NGK 8 heat range plug (or equivalent) and let us know how that goes. It may also be time to upgrade to a set of R8 coil packs.

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**adamleaf8601** · 03-27-2018 08:30 AM

Originally Posted by flowhigh

So the misfires stayed on 1&3 after you swapped the plugs, yes?

You swapped the old with new VW/Audi coil packs, yes?

How long ago was the carbon clean?

Don't know your mec's prowess, but he should've been able to tell if there was a timing issue if he had a capable scanner.

Some things I'd do is look at the injection IQ, injection quantity or injection quotient depend on who you talk to. I'd to this just to get a clue on how the injectors are doing. Ever try a couple of cycles of fuel system cleaner?

Mentioned a compression check, this could easily be done. I doubt this would be the issue though unless your engine had bad history or you like to beat on it.

I'd check fuel pressures, both the high and low sides.

I'd even borescope at least one of the intakes ports.

Honestly, you'd be better to find a really experienced independent Audi mechanic and get his opinion after his diagnostic.

Could be something really obscure and simple. But without taking some in-depth looking it's really hard to pin without more info. Get that oil leak looked at too.

So you just have the misfire codes?

YEs, the misfire stayed on 1 and 3 even after swapping the spark plugs. I did carbon cleaning less than 5k ago. We discussed doing a compression test but he ruled it out because the car drives fine. I've tried tonnes of bottles of fuel cleaner, nothing has worked. At this point I do believe that it is ignition related, as the check engine light comes on very shortly after I turn the car on, or when i am idling. We even replaced the PCV valve last week to try and fix the issue (because there was a pin hole leak in it), and we were both shocked that the misfire has persisted.

Basically, the misfire only occurs during idling and ignition. I have ordered a set of NGK spark plugs from amazon. We'll see how that goes.

**adamleaf8601** · 03-27-2018 03:22 PM

Bump

**mtroxel** · 03-27-2018 04:32 PM

Hate to say it, but lots of guessing here and it's getting expensive. You need to get codes, preferably VCDS. If your timing chain jumped a tooth, you'd see codes. And probably have a CEL. Might also be intake air leak, and sometimes that won't even show in a code. I suspect that's why someone asked you about oil leaking out the back of the motor. I've seen air leaks in a bad rear main seal. But you need more info at this point. We're all just spit-balling.

**flowhigh** · 03-27-2018 11:26 PM

Originally Posted by adamleaf8601

YEs, the misfire stayed on 1 and 3 even after swapping the spark plugs. I did carbon cleaning less than 5k ago. We discussed doing a compression test but he ruled it out because the car drives fine. I've tried tonnes of bottles of fuel cleaner, nothing has worked. At this point I do believe that it is ignition related, as the check engine light comes on very shortly after I turn the car on, or when i am idling. We even replaced the PCV valve last week to try and fix the issue (because there was a pin hole leak in it), and we were both shocked that the misfire has persisted.

Basically, the misfire only occurs during idling and ignition. I have ordered a set of NGK spark plugs from amazon. We'll see how that goes.

You've also swapped the ignition coils around?

The B8's had issues with the control runner getting stuck, but you only have the issue in 1&3 so that might be ruled out. I'd definitely take a close look at the injectors, some B8's had injector seal issues. Any smell of fuel? If your mec is good with an oscilloscope he'd be able to tell if they're functioning correctly otherwise try to get to a hold of a ross-tech cable and take a look at measuring block 015 at start-up and idle.

**Crucible35** · 03-28-2018 08:02 AM

How is your oil consumption? Your symptoms are very similar to what I experienced before having Fix1 & 2 of the oil consumption issue on my '09 A4. Turbo wastegate may also be a possibility with this one. Scan for codes. How is your oil consumption?

**adamleaf8601** · 03-28-2018 08:07 PM

Originally Posted by Crucible35

How is your oil consumption? Your symptoms are very similar to what I experienced before having Fix1 & 2 of the oil consumption issue on my '09 A4. Turbo wastegate may also be a possibility with this one. Scan for codes. How is your oil consumption?

My oil consumption is fine that was fixed years ago. What is turbo wastegate?

**flowhigh** · 03-28-2018 10:55 PM

Originally Posted by adamleaf8601

My oil consumption is fine that was fixed years ago. What is turbo wastegate?

It is small metal flap situated inside the exhaust side of the turbo controlled by way of the wastegate actuator. This small flap either allows or restricts the exhaust circulation and it's pivotal in the creation of your boost.

**adamleaf8601** · 03-29-2018 05:52 PM

Thankfully Audi was able to diagnose it today and updated the ECU. No more misfire after the update and throughout my whole day of driving.

**ak11214** · 03-29-2018 09:50 PM

Originally Posted by adamleaf8601

Thankfully Audi was able to diagnose it today and updated the ECU. No more misfire after the update and throughout my whole day of driving.

How much did audi charge u for the update?

**adamleaf8601** · 03-30-2018 01:08 AM

One hours labour

**ak11214** · 03-30-2018 06:04 AM

Originally Posted by adamleaf8601

One hours labour

Not bad and congrats on resolving it.

**Tyintegra** · 03-30-2018 08:10 PM

Originally Posted by adamleaf8601

Thankfully Audi was able to diagnose it today and updated the ECU. No more misfire after the update and throughout my whole day of driving.

What do you mean by "update the ECU"? Is there a TSB for this?

**flowhigh** · 03-31-2018 08:04 AM

Originally Posted by adamleaf8601

Thankfully Audi was able to diagnose it today and updated the ECU. No more misfire after the update and throughout my whole day of driving.

Did they give you a reason the update was necessary and what did the update consist of that resolved the misfires? Sounds like they might've just reflashed.

**adamleaf8601** · 04-01-2018 02:53 PM

I’m not entirely sure, but they did say they updated it. They said they watched the cylinders live and confirmed the misfires were occurring on 1 & 3. They stated that after they updated it though, there were no more misfires after the car ran for an hour. Perhaps it was a reflash; I’m not entirely sure but I’m just relieved it’s fixed. It was extremely annoying having the cel come on and flash randomly. Kudos to Pfaff Audi for their honesty and professionalism.

**Novarider** · 04-01-2018 03:15 PM

They let it idle for an HOUR?!? Can you post a pic of the work order they gave you?

**adamleaf8601** · 04-02-2018 09:05 AM

Originally Posted by Novarider

They let it idle for an HOUR?!? Can you post a pic of the work order they gave you?

They let it idle for an hour in order to be certain that the misfire was gone in cylinder 1 and 3 after the ECM update. That is pretty much all the work order says and that they want me to monitor it if the CEL light comes back on, they may have to replace the injectors.

**TJet1.8** · 04-02-2018 12:30 PM

Hmm...I must say this is the first time I've heard of a software update fixing a rough idle issue.
My 2011 and the wife's 2012 never had any update applied (that I know of).

The Guys at Pfaff are pretty good though, they have their own Tuning shop (Pfaff Tuning) and Motorsport division...so they are generally cool with minor mods.
Which location did you go to? Woodbridge or Newmarket?

**adamleaf8601** · 04-02-2018 12:46 PM

I was surprised too. It's been a couple of days and the misfire hasn't returned. I guess it also helps that I have remedied most of the other causes of the misfire in the past while. Pfaff tuning is not on site and I do not believe Pfaff Audi directly affiliates with them. I went to the Woodbridge location, I do not like the Newmarket location.

**flowhigh** · 04-02-2018 09:34 PM

Originally Posted by TJet1.8

Hmm...I must say this is the first time I've heard of a software update fixing a rough idle issue.
My 2011 and the wife's 2012 never had any update applied (that I know of).

The Guys at Pfaff are pretty good though, they have their own Tuning shop (Pfaff Tuning) and Motorsport division...so they are generally cool with minor mods.
Which location did you go to? Woodbridge or Newmarket?

It still hasn't been concluded that an actual software update was flashed.

**Crucible35** · 04-03-2018 05:08 AM

This sounds really strange to me. Did they give you any codes when they scanned the vehicle? Given they told you to keep an eye on the CEL.....they know it's coming back and they didn't actually fix the issue.

**adamleaf8601** · 04-03-2018 09:39 AM

Random Misfire, Cylinder 1 and 3 Misfire.

**Novarider** · 04-03-2018 09:56 AM

Originally Posted by adamleaf8601

Random Misfire, Cylinder 1 and 3 Misfire.

So it came back?

**adamleaf8601** · 04-03-2018 11:32 AM

Originally Posted by Novarider

So it came back?

No it didn't. I was answering the question about when they scanned the vehice before updating it.

**adamleaf8601** · 04-13-2018 07:48 AM

Something strange happened yesterday. I ordered Carista to enable a few features and for some reason the misfires came back immediately after turning on the features I want. Anyone have any thoughts?

**mtroxel** · 04-13-2018 08:02 AM

That might explain how/why a flash solved things. If I were you, I'd undo all your just did. If that fixes it again, then add your changes in one by one till you know what's screwing things up for you.

**adamleaf8601** · 04-13-2018 08:17 AM

Problem is I changed several things I don't remember everything lol.

**adamleaf8601** · 04-13-2018 08:21 AM

Originally Posted by mtroxel

That might explain how/why a flash solved things. If I were you, I'd undo all your just did. If that fixes it again, then add your changes in one by one till you know what's screwing things up for you.

Do you think these changed could void my warranty?