rs2 under power
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You was right.
The ISV was totally jammed in close position. I cleaned it again and oiled it with WD40 and it seemed to move smooth when I moved the slide. Now the car idles ok, but here and then the idle rpms seems to jump up and down for a while after high revs. Maybe the slide still struggles time to time..?

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Yes, I had the same. And I only solved it fully after I replaced my ISV.You was right.
The ISV was totally jammed in close position. I cleaned it again and oiled it with WD40 and it seemed to move smooth when I moved the slide. Now the car idles ok, but here and then the idle rpms seems to jump up and down for a while after high revs. Maybe the slide still struggles time to time..?
I cleaned it many times, but it would eventually just seize again...
Have you been able to check with vag-com? Maybe the closed throttle position switch is not giving signal correctly. That caused idle dipping and rough starting for me.Comment
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No, I haven't installed VAG-COM yet. I'm afraid to mess up my BMW-coding/diagnostics softwares on my laptop.
I use it only for bimmer codings. Maybe I have to make it done some day anyway...

Audi UrS4 Avant 2.5 20vt - twincharged - Project
Audi 80q B4 Sedan 2.2 20vt - Daily user
BMW 320d Touring e91 M-Sport - Daily user
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Hah... you will not mess anything up, don't worry
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Ok, I got the VAG-COM workin... It's only old 311.2 but it works fine. The cable seems to work with my BMW-cable drivers so didn't need to find new ones.
Got engine fault codes like this:
3 Faults Found:
00553 - Mass Air Flow Sensor (G70)
06-10 - Signal to High - Intermittent
00537 - Lambda (Oxygen Sensor) Regulation
08-10 - Control Limit Surpassed - Intermittent
00513 - Engine Speed Sensor (G28)
03-00 - No Signal
Last one is propably because I didn't have the engine running. Don't know about the lambda..? The probe is new, changed it before we remap the car.
Audi UrS4 Avant 2.5 20vt - twincharged - Project
Audi 80q B4 Sedan 2.2 20vt - Daily user
BMW 320d Touring e91 M-Sport - Daily user
BMW 740iA e38 - ProjectComment
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Your MAF is on it's way out and reading too high all the time.
Because of that too much fuel is injected. Motronic tries to compensate using O2 feedback, but you are running so rich, that it is past the compensation limit.
Clear those faults and see if they crop up again. If they do, I can say, that I am about 90% sure it is a bad MAF, if there are no mechanical problems.
Disconnect the lambda sensor and check AFR with a wideband gauge on idle and cruise.
Should be around 14.4-14.9 even without the lambda connected.
If it is significantly richer, replace MAF.Comment
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I used the RS2 MAF for a while, now I have the old MAF back. But with the RS2 MAF the mix was way too lean on idle, could the lambda limit been reach by then? Now when here has been dry roads without ice, and with the old MAF and full boost pull on 3:rd gear there have few times been big twitchs or cuts.
Does missfire or bad coil give fault codes? I have also a 1.8T coilset and harnesh waiting for assembly...
Hmm, must soon take the engine apart and put everything new, every probe... new RS4 MAF and drive over to Estonia.

Audi UrS4 Avant 2.5 20vt - twincharged - Project
Audi 80q B4 Sedan 2.2 20vt - Daily user
BMW 320d Touring e91 M-Sport - Daily user
BMW 740iA e38 - ProjectComment
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Try clearing the errors. If they are intermittent they might be caused by your old MAF malfunctioning.
Just clear them and then drive normally for a while. If they don't pop up and your fuel mix is alright, then you're good.Comment

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