Originally Posted by
declan morris
Hi all.
Just bought a 2wd 1990 cosworth with an idle problem. The idleing goes up and down plus when you put your foor on eccelerator pedal nothing happens until about half way down the travel of the pedal then it revs up slowly. Could this be the throttle positioning sensor. Any suggestions welcome.
Cheers.
had this with mine, it was hunting like mad, turned out to be a combination of things.
TPS was broke
ISCV (idle speed control valve) was clogged up, its the one that sits on the airflow meter
Lambada/HEGO sensor was broken (the one on the exhaust)
After replacing them it still had a slight hunting issue, turned out it was a tiny tiny vacumn leak on a bolt in the inlet manifold.
So id say its most likely one of them 4 if not a bit of all!
May also be worth taking out the idle adjuster and cleaning it, as even a tiny bit of shit on this can cause these issues.
type in "hunting" on the search my old thread and quite a few others should pop up on there!