I have a 98 UK turbo, terzo edition... I recently(2000 miles) had a full bottom end rebuild costing 2k....
Soon after I had the rebuild, the MAF sensor failed(the bit that connects to the air filter I think), so I splashed out £300 for a new one.

The problem is the revs jumping up and down.(hunting?) It only seems to happen once the car has warmed up, and sometimes it will only occur if I rev the car while in nuetral..It will keep happening evry time the car stops. The car idles between 300-1100rpm at worst, jumping up and down like a yo-yo....

Does any one have any idea what it could be, or how to fix it?????

Has been doing it for a month now with no change??
Could it be the Idle control valve??/ If it could be , where is it located on the engine???

Thanks, help is much appreciated...

 

icv on my 99 model is on top of throttle body,very easy to get to.

 

similar thing with mine, check codes and it should tell u think it is 31 for idle control valve. if this code flashes take it off and give it a clean followed by ecu reset b4 splashing out on 1 - quite expensive to buy.