Wrenchin... Adventures under the hood... Put em here.

[fatnslow]

Unfortunately the code reader is gonna say "Misfire Bank 2" and you're gonna be wondering if its everything from a bad spark plug to a blown head gasket the whole way home. But you'll at least know it's on Bank 2 not Bank 1.

Maybe he'll get lucky and it says go steal a Hyundai/Kia or misfire cylinder 3 and he can try switching coil 2 to 3 and see if the misfire moves.
Possibly save himself $4-500.

[MontuckyFried]

Seems like a reasonable place to put this:

I have a 2013 Audi allroad with 150k on the clock. Drove ~500 miles to a work thing. About halfway there it started to misfire under hard-ish acceleration or when maintaining speed up a hill at 80mph (~2,200 rpm).

- this happened within a couple minutes of filling up. Bad gas?

- it feels super similar to when I had a bad coil in the same car. Difference being with the coil it cleaned up at higher RPM but here it gets a lot worse at higher RPM.

- at first I revved it because of course. It threw an EPC light but no check engine. I struggled it over to a gravel lot off an exit with a super rough idle and checked all the coils and cables and looked at it for a while and clucked my tongue. When I started it again the EPC was cleared and the rough idle was gone. (Limp mode?) Eventually it threw the check engine but the EPC has not come back.

- When I got to town (Detroit) it was just fine cruising around town as long as I stayed out of the turbo. It also had no problem getting up to 90 as long as I babied it up there.

So what to do? Find a local shop or dealer that I don’t trust to pull codes and fix it and hope that the whole thing doesn’t add a night to my stay? Go to autozone and have them pull codes and try replacing a coil/plugs in their parking lot with their tools? Just limp her on home?

What say ye?

I recently had VERY similar symptoms on my recently revived Volvo. I lucked out and all it ended up being was a grounding bolt connecting the coil packs to the engine that had backed out. Evidently threads on the old bolt had worn or something. Picked up a new bolt from ye ole Ace Hardware for like 20 cents, CEL went out on its own, and engine's been running good as new ever since.

Now before THAT, the rough running was due to ancient gas that had been sitting in the tank since the car broke down like a year ago. Couldn't syphon the gas out, so diluted best I could with fresh 93, dumped in a bottle of SeaFoam and a bottle of Cataclean since I was also getting that rotten egg smell, and it helped out within minutes. Ran through that whole tank and refilled with more Shell 93. If you got a batch of bad gas, doing some additives and fresh fuel might help.

I'd seriously start with examining your wiring and grounds though. If your Audi's like my old A4 was (and I believe it is), the wiring to each coil pack goes through a plastic assembly, where you unplug all the coils and lift up the whole thing. At least on mine, it was a point of contact where the wires had been rubbing against it for ages and I found a few frayed wires in there, which could absolutely cause the issues you're seeing. I simply wrapped the problem wires and made sure that plastic assembly was snapped together correctly (there WERE some points on it that were broken and had to be taped shut). Examine all of that and check the grounds connecting the coils to the engine. I believe all the coils connect to a single ground or two at that comes out of the base of where all that wiring comes together toward the rest of the wiring harness. If you see any frayed wires or trouble spots, score yourself from TESA tape. It's this sweet fabric high-temp tape I got for wiring harness work. Will be better than factory! Your car's getting to the age where there may very well be some funny wiring things going on. German plastics in particular get pretty brittle by this point. I replaced miles of split loom and other bullcrap on my A4. Haha.

[Timberridge]

Have Aldo look at it. He'll get it running like a Swiss watch.

[BmillsSkier]

Seems like a reasonable place to put this:

I have a 2013 Audi allroad with 150k on the clock. Drove ~500 miles to a work thing. About halfway there it started to misfire under hard-ish acceleration or when maintaining speed up a hill at 80mph (~2,200 rpm).

- this happened within a couple minutes of filling up. Bad gas?

- it feels super similar to when I had a bad coil in the same car. Difference being with the coil it cleaned up at higher RPM but here it gets a lot worse at higher RPM.

- at first I revved it because of course. It threw an EPC light but no check engine. I struggled it over to a gravel lot off an exit with a super rough idle and checked all the coils and cables and looked at it for a while and clucked my tongue. When I started it again the EPC was cleared and the rough idle was gone. (Limp mode?) Eventually it threw the check engine but the EPC has not come back.

- When I got to town (Detroit) it was just fine cruising around town as long as I stayed out of the turbo. It also had no problem getting up to 90 as long as I babied it up there.

So what to do? Find a local shop or dealer that I don’t trust to pull codes and fix it and hope that the whole thing doesn’t add a night to my stay? Go to autozone and have them pull codes and try replacing a coil/plugs in their parking lot with their tools? Just limp her on home?

What say ye?

When is the last time you had a carbon cleaning on the intake valves?

[MontuckyFried]

When is the last time you had a carbon cleaning on the intake valves?

Ohhhhhhh yeah! That's right! His symptoms DO sound like a lack of carbon cleaning, something highly recommended for Audis of course. Good call. I'd take a look at dem intake valves stat, Mustonen.

[Mustonen]

When is the last time you had a carbon cleaning on the intake valves?

Like, seafoam?

Never.

Current plan of attack is to put some heet in there and fresh gas and drive home. Might skip autozone and pulling codes for the moment just because I’m not realistically doing anything with that information before I get home (provided I actually get home). Think I should toss in some seafoam instead?

[Timberridge]

Wait, this has the 2.0T 4 cyl? Oh boy. The engineering team who built that engine should have one strapped to their ankles and thrown in the Rhine.

[basinbeater]

Yeah, those 2.0t. cam followers on the hpfp that eat themselves, carbon buildup on the valves, pull the entire front end off to do a timing job. I had an audi once. Once.

[Mustonen]

Oh, I had all kinds of fun with the timing chain 80k ago. Ended up being a couple weeks in the shop and $1200. My local mechanic was pretty good at tearing the front off to get at it. Since then it really has been 80k mostly trouble free miles, save for plugs and coils and bearings and a minor recall.

On balance, I’ll take it. But I’d like to add another 50k still.

[MontuckyFried]

Like, seafoam?

Never.

No, no. Not like Seafoam. If I'm not mistaken, due to the direct injection design, the standard fuel additives aren't near enough to clean off the valves. For normal operations on these, I've heard to (A) use good quality premium grade fuels a la Shell, Chevron, etc., (B) give 'em the old fashioned "Italian Tuneup" frequently, lots of full throttle pulls and long highway stretches to get everything hot enough to burn off the crud, (C) more frequent oil changes than manufacturer recommends, so every 5K as opposed to 10K, which helps keep (D) a clean PCV system, replacing those parts when needed, but ULTIMATELY you'll need (E) a full blown valve carbon cleaning service, with many doing a walnut shell blast. It's not cheap BUT with all of the above recommended maintenance (along with your timing chain services you had done already), these motors can run well for a long time. They're better than people give them credit for BUT you gotta stay on top of these items. Still cheaper than a new motor and definitely cheaper than a replacement car so absolutely worth it if you like your ride!

[Mustonen]

I do all of those things. Most recent fill up that preceded problems was shell, actually. I can’t imagine carbon buildup would manifest so suddenly?

[powdrhound]

No restoration kit would have stood a chance.

How did they get this material past the federal safety regulators?

[MontuckyFried]

I do all of those things. Most recent fill up that preceded problems was shell, actually. I can’t imagine carbon buildup would manifest so suddenly?

It IS quite possible you got a tank of tainted gas from that last fill. That said, aside from the routine operating tips, have you had the full blown carbon removal service done like media blasting?

[SumJongGuy]

Unfortunately the code reader is gonna say "Misfire Bank 2" and you're gonna be wondering if its everything from a bad spark plug to a blown head gasket the whole way home. But you'll at least know it's on Bank 2 not Bank 1.

Had that on daughter's fit recently. Shop was sure it was a coil so they changed that coil. 3 weeks later and 800 miles past the 100 mile OBC reset threw another code for another bank/cylinder. Replaced the other 3 coils and no issues since.. So, it could be something brewing more than just bank 2. Two months + with the 4 new coils and all good to go..

[MontuckyFried]

Had that on daughter's fit recently. Shop was sure it was a coil so they changed that coil. 3 weeks later and 800 miles past the 100 mile OBC reset threw another code for another bank/cylinder. Replaced the other 3 coils and no issues since.. So, it could be something brewing more than just bank 2. Two months + with the 4 new coils and all good to go..

That could always be it too. On the plus side, VAG coils are DIRT cheap for whatever reason. I think I spent around $17 a pop on mine for OEM ones. So honestly if you do one, might as well do 'em all. They're cheap and it's an easy job. Could toss in some new spark plugs too for good measure unless they've been done recently. And again, can check the integrity of the wiring and grounds while you're in there.

[Timberridge]

Here ya go Montucky...

[basinbeater]

My understanding with those direct injection valves, is that the EGR or CCV system gums up the valves, and because there is no fuel ever to wash the valves and the intake ports, it gunk's up and then they run like crap. Have to pull the intake mani off and walnut blast them to clean em up. Same problem exists with the bmw n54/n55 and just about every direct injection engine.
The solution to prevent it from happening is to install a catch can inline of the CCV/EGR system. Then the gunk doesn't end up there in the first place.
This guy does a nice job covering the topic.
https://youtu.be/T-B4VRxAtbw

[Norseman]

Running shitty on boost but mostly fine without... and sudden onset... sounds like maybe an intake leak?

Logged O2 data showing anomalous rich (post turbo leak) or lean (pre-turbo, post MAF) might point this way.

Sounds less likely than the already-familiar coil and/or wimpy blown-out spark.

[MontuckyFried]

Here ya go Montucky...

WOAH!!! Now THAT'S a neat find! Imagine if somebody found an 850R with that mileage/condition. Unreal.

It's up on BaT now. Currently sitting at $17.5K : https://bringatrailer.com/listing/1996-volvo-850-11/

[gravitylover]

Damn, P076a popped after the tranny dropped into third very roughly and wouldn't shift after that. It got me home but it's in limp mode and won't rev over 3k. Looks like I'm not working again until I learn how to change tranny solenoids

[gravitylover]

Damn this is an involved job that's really tough with the tranny in the car. Fack... The parts are relatively cheap but I can't afford the downtime right now. Damn.

[Timberridge]

Montucky seems to be slowly working his way out car repair hell. Gravitylover not so much. Hoping you turn the corner one day GL.

[simple]

Damn this is an involved job that's really tough with the tranny in the car. Fack... The parts are relatively cheap but I can't afford the downtime right now. Damn.

You sure? Solenoids are usually right there when you pull the pan off.

[MontuckyFried]

Damn this is an involved job that's really tough with the tranny in the car. Fack... The parts are relatively cheap but I can't afford the downtime right now. Damn.

Aww man. That sucks.

[MontuckyFried]

Montucky seems to be slowly working his way out car repair hell.

Indeed! I feel quite blessed to go from 1 questionably functional car to 3 that are all running quite well! Think I finally got the hang of this whole Volvo thing! 2 successful head jobs in a year. I feel good. Last week I finally got rid of the garbage tires that came with the C30, swapping them out for some Pilot Sports. BIIIIIIIIG improvement in ride, handling, acceleration. Other than that, it's been totally problem free for a long time now! WTF? Something doesn't seem right with that. In fact, ever since getting my S60 up and running, my weekends haven't been completely committed to crawling under the hood of a car. Almost seems weird. Now I get to do OTHER projects around the house. Haha.