help!!!! fast idle on hot start up

[maggott84]

hi i have a mk4 golf gti 1.8t with a problem that is driving me mad .
when started in the morning from cold the car runs perfectly as it should, il stop and switch off for a few mins (i.e. popping to the shop), il jump back in and start her up again and the revs rise to 2000rpm for a few seconds then idles at 1200rpm.
there is also a slight hesitation on the throttle when parked.
i had it plugged into a vagcom and it showed that the temp sender was faulty so i changed it and for about 4 days it seemed like it had cured the problem untill friday last week when the problem came bk .
if anyone could help me it would be much appreciated thanks

[Immortal]

I had the same thing start a couple of weeks ago.

Initially a scan said temp sensor, so like you I swapped it out. Then it came back a couple of days ago (along with a major flat spot in my boost), now it appears to be the lamba sensor

Hope this helps

[maggott84]

hi mate thanks for ur reply i have had a feeling it might be a lamda sensor. iv got it booked in at a garage call C.G Proformance on friday i shall let u no the out come. have u changed the sensors if so has it made a difference? thanks again

[maggott84]

does any one no if a EGR valve or a cold start valve would corse the problem i am getting ??