RS3 idling issue

[Nightstorm18]

Hi all, hoping you can help me as I'm getting nowhere with my Audi dealership in Australia trying to fix an idling issue.
Car is a 2016 PFL RS3 with 40,000km on the clock. Had it for 6 months and no issues and then had cold start issue where it would be very rough on start up and some times stall, but never during driving, I also did notice performance issue with revving occurring and not being able to put power to ground effectively. I had several limp-home modes occur as well.
Audi advised car had been tuned (which I wasn't aware of when I purchased it) so they weren't prepared to do further diagnostic work. So I managed to get the Stage 1 REVO tune removed and flashed back to Audi factory settings. As a result they were able to do several updates and replaced the PCV and said it's likely been fixed. Cold start issue improved but still rough and revving issue while driving and idling intermittently continued (hunting) and performance issue continued.

Audi then replaced fuel pump (with another RS3 that had been traded in for sale and was awaiting parts) to test if this was the problem. For the first 48 hours it almost seemed normal again but then progressively got worse again - revving issue while driving and idling intermittently (hunting) and performance issue. Car revs by itself intermittently either when cold (50 degrees oil temp or hot 95 degrees oil temp). Using a mates VCDS it has recorded multiple occurrences of P050700 - Idle Control System RPM Higher than Expected. Googling and reading what I can find on forums I haven't seen this code with the RS3.

Keen to get people's thoughts/ help on this but I'm thinking:

• Vacuum leak / air leak in the boost - Maybe a leak - split pipe Apparently not uncommon with the PCV valve hoses as well?
• Air intake - I note the air filter has been replaced with a non-standard one – apparently can be over oiled and clogs sensors - I note that the RS3 uses pressure sensors to work out air intake – can these be inspected / cleaned?
• Throttle body / idle control valve
• fuel injectors / stuck injector
• speed sensor faulty
• Crank sensor faulty
• Faulty ECM
• N205 Cam Valve / Camshaft Adjustment Solenoid

 

[Silky67]

Did you get any resolution on this, I have what appears to be an identical issue. Like you, I’ve replaced various components like plugs, coils, vacuum hose and each time the issue stops for anything from an hour to a week and then returns.

 

[fangcatoo]

Hey,
I'll tell you what happend to me maybe it'll help, when my turbo broke completely it ****** with the A/F ratio, and it worked really rough and stalled on me, firstly it really sounds like a vaccum leak, before you go inside the engine I suggest you look at the turbo to see if the compressor/westgate isn't stuck, you need to find the component ******* with ur A/F ratio.
is your car running rich?, if so are you getting misfires? in what cylinder?

 

[Silky67]

Hey,
I'll tell you what happend to me maybe it'll help, when my turbo broke completely it ****** with the A/F ratio, and it worked really rough and stalled on me, firstly it really sounds like a vaccum leak, before you go inside the engine I suggest you look at the turbo to see if the compressor/westgate isn't stuck, you need to find the component ******* with ur A/F ratio.
is your car running rich?, if so are you getting misfires? in what cylinder?

Thanks, not running rich or lean or misfiring. It was running a stage tune so reverted to stock VAG tune but still getting intermittent hunting on idle, occasionally stalls when cold and bogs down on light throttle but not always. Tuner was able to record a log file when it displayed symptoms. Sent this to Germany for a second opinion but came back saying tune is A1 and live data is good. Also checked PCV valve which is fine. He suggested carbon deposits on injectors/intake. No error codes at all.

 

[fangcatoo]

Thanks, not running rich or lean or misfiring. It was running a stage tune so reverted to stock VAG tune but still getting intermittent hunting on idle, occasionally stalls when cold and bogs down on light throttle but not always. Tuner was able to record a log file when it displayed symptoms. Sent this to Germany for a second opinion but came back saying tune is A1 and live data is good. Also checked PCV valve which is fine. He suggested carbon deposits on injectors/intake. No error codes at all.

Could be a vaccum leak from the injector O-ring , are you hearing strange noises in the cabin? no the exhaust flap rattle, im speaking about ticking sound, almost sounds like the engine working but more ticky