Audi A4 1.9TDi revving and idle issue

Honest John Back Room » Technical matters
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Fri 24 Mar 2006 10:27
Audi A4 1.9TDi revving and idle issue - rew62
I have an 2002 A4 Avant 1.9 TDi 130BHP with an annoying problem.

When starting the engine from warm the revs briefly rise to about 2,000rpm then drop back to normal. Additionally, the idle speed occasionally sits at 1200rpm or so, then drops back to normal (800-900rpm). I am wondering if the two fault are related.

Points to note,

- the overrevving does not occur when the engine is cold
- the overrevving happens say 2 in every 3 warm starts
- my Audi dealer has had the car in for service but found no fault
- I start the car as I always have - no accelerator

Not a serious problem I admit, more annoying, but the overrevving must be doing a small amount of harm. I'm guessing a faulty sensor may be to blame.

Any advice welcome.

Andrew Dawkins
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Fri 24 Mar 2006 21:48
Audi A4 1.9TDi revving and idle issue - Roly93
Did the dealer say anything about a possible throttle-position sensor problem ?
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Fri 24 Mar 2006 22:09
Audi A4 1.9TDi revving and idle issue - Screwloose
Andrew

The coolant temp sensor intermittantly sending the wrong info to the ECU can cause this too.
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Mon 27 Mar 2006 12:35
Audi A4 1.9TDi revving and idle issue - rew62
How easy is it to replace this and/or the throttle position sensor? I am happy with spanner work etc. Also, any idea on the cost of these sensors?
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