172 Mk II Ph 2 Idle Problem

[sn00p]

I've searched and found a few people who've had this problem, but none seem to be exactly the issue I'm experiencing.

If I'm driving the car and dip the clutch to slow, the revs will go up to 2K and stick there until I've come to a complete standstill at which point they drop down to normal.

The car is very slow at coming off revs - makes the gear shifts nice and smooth but it's very weird to drive.

If I drive along in second gear and release the clutch, it's almost like the throttle is still being pressed and rather than slow down quickly, the car will quite happily keep going, if I put my foot on the clutch I can see the engine sticking at 2K and it won't drop until I come to a complete halt.

It's obviously quite irritating now, and so far I've changed the throttle position sensor, plugs, coil packs and throttle body and it still bloody does it.

Any ideas?

Cheers

 

[sn00p]

Weird, the car has been off the road for 2 months with this fault, in that period it's only done a couple of journeys one of which was 200 mile round trip, it's had the same fuel in since the problem started.

I had no choice but to use the car this morning for a hundred mile journey to the office, so put a half tank of fuel in (was on a quarter) and all through London the idle revs were misbehaving, I could feel the car struggling, then when I was going down the motorway I noticed that the car felt different in fifth, responsive, came off the power properly.

When I got back on b roads, and was slowing and using the clutch the idle was behaving normally, the car felt back to normal, full power.

Now I'm wondering what the problem is, does it only appear when the car is cold? (the car exhibited the problem for at least an hour this morning, so doubtful on that one!) or has the journey somehow cleared whatever was causing the problem or maybe I had a fuel contamination issue, the original tank of fuel that was in it when the problem appeared will have completely been used now or at least severely diluted.

I guess I'll find out more tonight when I drive home.