Revs lift and hang while coasting....

[audi_do_dat_den]

Hello folks....
This is something I haven't been able to get a defined answer on so far, but maybe you can tell me if its right or wrong.

When im coasting or rolling along in a line of traffic, with the clutch pressed in and either in gear or neutral, the revs hang at around 1200 - 1500 and then as soon as I come to a full stop, they drop to normal - 900 ish.
Even if at barely walking speed, the revs hold up until actually stationary...... but It seems to be only with the clutch pressed in.

Is that a driver aide or is there something wrong like the clutch switch goosed for instance.....?

Im certain I have a vacuum leak somewhere and is it possible that its part n parcel of the same problem?
The revs have been a little erratic lately and sometimes with town driving, I suffer a little from the embarrassing stall of shame when trying to manoeuvre slowly.....

Any help or advice is welcome. Cheers in advance.

[TonyHayers]

Quite possibly a vac leak or could be dirty/faulty MAF.

[coldo]

Does your cruise control work?

If not, all things point to clutch switch. It's a common fault. Even if the CC is working, i'd change the clutch switch, just to rule it out - it's cheap and an easy DIY job on your driveway!

[PetrolDave]

Does your cruise control work?

If not, all things point to clutch switch.

+1

Revs not dropping when you change gear is most often due to the upper clutch switch faulty.

[chris_m]

Do you have a cold air feed by any chance? I had quite a severe hunting problem not so long ago, the car actually stalled whilst coasting. A k&n panel filter was the culprit believe it or not.

[audi_do_dat_den]

Cheers for the replies folks,

My cruise control works fine but that doesn't entirely mean that it couldn't be the switch... so im going to order up a new switch from the part number on the FAQ, worth the cost if even just a process of elimination.
Ive also spoke to VAGTECH about getting a look over for finding the vac leak, they suggested that at my mileage, its probably good to do the inlet manifold chamber de-sludge and have a stage 1 REVO plus delete the tumble flaps.....
Im not keen on re-maps in general as im sure that's what killed my old 3.2 TT.
Plenty of beans there for me already, but if the problem can be solved and a de-carbon/sludge done together, it might be good.

I will report back with the results.....

[obikaii]

Be careful when you buy the clutch switches,I went to 3 different autospares places near me,& none of them had the correct switches,but when they typed the code numbers into their systems it came back with a different switch,I think it was the brake light one,which I bought,as it looks very similar to the lower blue clutch switch,I ended up getting the correct ones from my local audi dealership,around £30 for both.

[audi_do_dat_den]

Nice one obikaii,
I will save the stress and take the hit with Audi then.
Still a bargain if it helps sort it!
Thanks again

[nij]

It could be the Oil Separator/Breather Valve (PCV) or the Air Box Solenoid Valve.

I had similar issues and replacing the PCV solved the problem.

There's a thread about it: viewtopic.php?f=35&t=96292

[audi_do_dat_den]

Nice one nij, i'll check that out too.
Im away from the car at the moment so i cant check the filler cap pressure/vacuum trick etc.

Im not using much oil though, well not as much as youve experienced but im getting through a liter every 3k miles or so.
I was considering buying one of these usb borescopes and try to peer into the inlet manifold space.
If its all gunged up ill get it in for the desludge and get all the pcv system changed out including the nasty little connection under the manifold in the vee.

It does seem to have very similar symptoms as you were getting.

[nij]

A litre of oil every 3K miles is a little above average. Mine wasn't using oil at all and when it finally give up, it made a loud whinning noise one morning, probably due to excess vacuum in the cylinder head.

[edge]

Did you get this sorted? Mine seems to now do the same thing... was worried it was the MAF!

[audi_do_dat_den]

Did you get this sorted? Mine seems to now do the same thing... was worried it was the MAF!

Hello mate, ive bought both clutch switches from audi and just waiting to get in there and change them.... i will post up what the outcome is.
I still suspect a vacuum leak somewhere though.... ill let you know

[scaghead]

Didn't klauster have the same a couple of years ago? Think it was something like a oil separating valve or something... I remember some have had this thing moved when they have a carbon clean... Good luck anyway fella...

[edge]

VAC issue for me, tiny break in one of the pipes, once it was found and swapped out its alls good!