S4Patrick

I have a 1999 A4 1.8TQ It's got about 35,000 miles on it...

For the last week, when I 1st get into the car to start it, the engine revs. up to 1,500 rpms--normal. But when it starts to drop back down to normal idle (approx. 900 rpm's), it goes down to maybe 400 rpm's. This is where the engine struggles to keep running and almost dies. It goes down to 400 rpm's for a second, then goes back up to 1,000 back down to 650 rpm's, then to about 900 rpm's where it is at normal idle. All of this volitile rpm swinging happens in about 4-5 seconds.
I know that engine will change their rpm's a little while at idle, but this is not right.......engine wants to die, but then comes back up and only on 1st initial start up.

Its never done this before, and when I stop the engine and then start it again, it won't do it. It only does it when it's been sitting for about 5-6 hours.


Please shed some light as to what this may be..........

Thanks.....to all that reply.

--Johnny C.

What could this be?.........spark plugs?.......

WJM

might want to replace it...this has been a common symptom of a dirty fuel filter

PGP

If you can catch it when it does it tap on the valve and see if the idle gets better.

jetboy737

vaccum leak

S4Patrick

remember, this only happens on cold start ups, and lasts for a few seconds.....