right, i have a magneti marelli 2.5 (250kpa, prt 06/00) fitted to my car but the engine won't idle right, it runs rough as a dog. but soon as i put some revs on it clears and seems fine. same story on the road, idles crap but boosting its fine?

also if i dip clutch when moving, engine idles at 2500rpm and doesnt come down till you stop moving. you can feel it pulling as well if you let off accelerator totally, its behaving like a cruise control!!

could this be a faulty map sensor?

thing is all this is fitted to a renault clio f7p turbo, an engine that was never sposed to have turbo on it. i have been running a renault 21 turbo original fit map sensor and had to chop the magneti one into the wiring loom. i have double and triple checked the wiring diagrams and its definately wired in the right way, besides any other combo of wiring and car wont even start, let alone idle. with the old sensor on it runs fine on idle but dont want to boost it with that one on as the ecu map and injectors are for 2.5bar sensor

i have tried asking on renault forums but to no real avail as not too many of these turbo'd f7 series engine about

any advice/experiences much appreciated

cheers

Ben