Boilers

My '09 A4 2.0T P+ with 50,400 miles is having cold start issues. When I start the car after it has sat overnight or been parked all day while I'm work, the RPM's shoot up to around 1200 rpm, which is normal. But as it sits there idling at 1200 rpm, the car shimmys (feels like it is swaying side to side). Then after roughly 30 secs, the revs drop down to 800 rpm, again normal, and the car feels fine (no shimmy). I put the car in gear, in this case reverse, and the engine feels like it's on the verge of stalling. Happened a few times over the past week. Then this morning the Check Engine Light came on.

Dropped the car off at the dealer. The car threw out cold start misfire codes when diagnosed. I was told that there is a software update that should fix the problem. Dealer kept the car overnight and will start it up in the morning to see if this fix takes care of the problem

Also been noticing, on occasion, rough shifts between 1st & 2nd and 3rd & 4th gears. Doesn't always occur. I thought I've read that a software update also fixes this issue, but can't remember where I saw that.

Anyone else having similar issues? What was the solution?

Boilers

Well, the software upgrade was not the fix. Dealer started up the car this morning and the CEL came back on. They are currently cleaning the carbon off of the intake valves. Will keep the car overnight and start her up in the morning.

Wondering, if this works, does that mean every 50K miles the intake valves will need to be cleaned? In 200,000 miles I never had to do that with my '99 1.8T A4 Q.

IzzyA4B8

I had somewhat of a similar issue.. My Audi (2010 A4 s-line) was "puttering" on cold-starts. There were no reported issues when I had it checked at the dealer. But I soon realized that it was the fuel that I was putting into the car. I was usually filling up at Petro-Canada, 91 Octane. I've never put anything lower than 91 into the tank. Unfortunately, it turned out that the petro-91 has a percentage of ethanol in it. This fuel was what was making the compression run poorly. Since then, I've switched to Shell's V-power 91 octane (0% ethanol). Ever since, it's been running very well, no issues.

Boilers

The software update in conjunction with cleaning the carbon build-up from the valve intakes fixed the problem. No more check engine light, no more motor hesitation....she's running like new!!

I only use Shell VPower or Chevron Supreme, but some ethanol is blended in with the gas. Dealer suggested using a fuel additive/cleaner a couple times a year.

audi8k

Hm, direct injection means that the fuel does not pass through the intake valves. Ask the dealer what part needs to be cleaned and how an additive will help.

QUA77R0

hmm almost identical symptoms and Audi replaced our intake under warranty...again.

agree with audi8k. Is the dealer admitting that after only 50k, that carbon buildup was preventing the valves from seating? I've never seen carbon buildup in a sub 100k motor but the more I hear about long service intervals, the more this seems to be a possibility...maybe that should be probability...

Boilers

Looking over the work order....

........
Intake Manifold Remove & Install
Variable Flap
Valve Repair
Software Update

The fuel injectors were being swapped to troubleshoot. Ater removing the intake manifold, found that the valves had excessive carbon build-up. Valves were cleaned of carbon build-up. Fuel injector cleaner added before start up. Let vehicle sit over night. Restart, engine running smooth and no misfires.
........

So appears there was a bit more than just the software update and valve cleaning. The dealer apparently had been talking to Audi to diagnos/solve the issue.

@ QUA77R0 ~ I've never had a carbon build-up issue either, but based on the constant cleaning of my exhaust tips, the 2.0T motor seems to produce a lot more carbon, even though I service every 5K miles.

Boilers

@ QUA77R0 ~ based on your pic, assuming you have the STaSIS flash? How do you like it? Any issues with it? I'm thinking of getting it.

QUA77R0

PM sent

B-B8

I have these identical symptoms. Except my car is dying as i back out of the driveway just after starting it. Once it warms up, it doesn't die anymore. But the strange shifting that you were having, did that also go away after you cleaned the valves and software update? Do you know if the update is an Audi only update? Like, they have to do it?