Idle problem

**Spelly** · 18th January 2009, 23:28

My Gsi has recently developed and unusual idle problem.....
Idles fine when started from cold but after ive drove 10 miles or so and the engine is up to temp the idle is up / down
If i pull up to junction in neutral the revs drop to 750 ish then slowly increase upto 1500ish and then drop off again to 750
the car is otherwise fine. I have removed the throttle body assembly and checked / cleaned it and all seems ok

Anyone any suggestions as to where i start

Thanks in advance.......................

**poves** · 19th January 2009, 00:16

I think this is common , some people have ended up getting new or second hand throttle bodies from what I remember .

**Duncan** · 19th January 2009, 00:18

Have you checked/cleaned the idle control valve?

**900ss** · 19th January 2009, 00:59

Should you need one I've a tbh from a sub 35k GSI

Looks mint for what it is, tho not sure of price mind.

**Spelly** · 19th January 2009, 01:22

I have stripped and checked the ICV / Throttle body twice with no luck
I have operated it with the throttle body plugged in but not attached to the car (sat on top of the inlet) and it seems to operate ok
Reluctant to replace it as it may not cure the problem
Bet they're expensive too.............

**poves** · 19th January 2009, 01:38

I sold mine for £50 from a 41000 mile elite , as a rough guide on cost .
The chap who bought it had the same symptoms as you describe.

**s0501291** · 19th January 2009, 01:42

If the idle keeps rising and falling, sounds like some sort of vaccume leak. Have you checked all the hoses? (I had a 1.8 focus before I got my Vectra C, that had a similar problem, turned out to be a split hose)

**Spelly** · 19th January 2009, 02:11

Ive breifly checked the pipes for leaks but couldnt see anything
no noises either(like theres a pipe off)
It only does it when up to temp
If it was an air leak then im assuming it would do it regardless of engine temp

Many thanks

**gtr1000** · 19th January 2009, 09:46

Cooalant temperature sensor? If for some reason this is dodgy, it will think, at times, that the system is "cold" and overfuel/run rich. Just a thought.

**Spelly** · 20th January 2009, 00:08

Thanks for the help...

I think is probably the idle vavle / throttle body housing thats causing the problem. It seems to be a problem with the 3.2 which is solved by replacing it

Anyone any idea how much these are new...?
Or where i could get one second hand.........?

Back to using my trusty cav turbo till i get it sorted.......