Audi 2.3 20v Doch 7a idle problem

[ACQ]

I have problems with idling. Engine idling is fine for about 5seconds after start and then revs go down. When engine is warm up, it keeps revs but engine is shaking... Car is ok on running and only idle problems. Tried to change idle valve, ignition coil and distributor, idle sensor, spark plug wires. Must to say that changed parts was not new, but dont want to buy everthing new and waste the money. Maybe someone had the similar problem.

https://www.youtube.com/watch?v=g97Ew_u_AB4

[newsh]

Air leak in inlet tract, check the smaller hose underneath the main rubber hose is good and is plugged in. Renew any small cotton braided vacuum hoses.

[Mikes2]

early or late 7A ? Mines a late car and I had similar. The small ribbed hose from the inlet manifold to the ISV had a split

[ACQ]

Early model. Hose between inlet manifold and maf is good. I will try to check if other hoses are leaking

[Lago Blue]

ACQ,

Just to add to the above good advice, perhaps you already recognize that at idle, because air consumption is going to be very low, any small un-metered air leak(s?) into the intake tract are going to have their largest bad effect precisely then. This thread will give you a broad list of items to survey / clean / confirm / test and work through:

https://www.s2forum.com/forum/technical/engine-and-turbo/2044204-engine-stalls-right-after-starting

[steve briance]

Yep. Small air leaks can cause trouble. Noting how many turns it takes to undo, remove the idle speed screw and look at it. Replace the tiny o ring and screw back in the same number of turns.

I'm not saying this will solve it but air getting in here will be after the maf so the necessary fuel will be missed.

Before I changed my. O ring it was surprising how much vacuum was leaking out /air getting in. Put finger over the end of the 'tube' where the screw is and see how much it sucks on your finger.

[ACQ]

So problem solved. Air was leaking..

[Lago Blue]

ACQ,

To perhaps help others reading this with similar issues, please say exactly where and what you found.

[newsh]

So problem solved. Air was leaking..

Where was the air leak?

[mihai_antony]

Me too I am curious

[John.]

Me too, always good to hear how a problem is cured.

[ACQ]

Sorry for a late reply. So problem was solved for a short time. Was leaking hose behind of inlet manifold. But problem is with ICV changed them 4-5 times because I have them many and no better idle... Cleaning doesnt helped. So I disconected it and idle is fine. Also car runs more better. Only cold idle is bad for 20s...