Rough Idle on start after engine is warm

[mgroth]

Originally Posted by Lapister

I'm assuming you took off the TB and you cleaned both sides of the butterfly valve? First time I performed the service it ran rough too. Found the TB connector slightly loose ( not making). The point I'm really trying to make here is some people clean just the outside area of the TB and when they go to start the car it runs even rougher cause all the gummy deposits are suspended on the inside of the butterfly valve and feathering the slightly open valve reducing a smooth flow of air.

I did clean butterfly on TB . However I did not clean the second butterfly in the cross pipe near evap purge valve.

[mgroth]

I put in a new MAF sensor and problem went away.

My original MAF started throwing codes a yr ago. I cleaned it and that worked for a while. Then after a while codes came back. So I bought a new eBay MAF (Chinese) . Worked great for a while. On a hunch I installed the old one last week and the rough idle on warm start was gone. But CEL was back. so I just bought yet another MAF, this time a Bosch. I cleared CEL code and idles fine now.

Thanks for all suggestions and input.

[Gelbster]

So we all failed !Nobody diagnosed MAF
I am puzzled by the solution. In theory you could have just disconnected the MAF and the default would have produced reasonable performance and idle.
What gave you the idea to replace the MAF ?
Thanks for the warning about cheapo EBay MAF being short-lived !!!

[mgroth]

Originally Posted by Gelbster

So we all failed !Nobody diagnosed MAF
I am puzzled by the solution. In theory you could have just disconnected the MAF and the default would have produced reasonable performance and idle.
What gave you the idea to replace the MAF ?

Porsche friend said he had similar issue on his Audi and MAF was the issue.