[ScottyTurbo]

Hi everyone! I'm new to this so bare with me, ill try describe everything the best I can!

I bought a mk5 fiesta (51plate) with a 1.7 puma conversion already fitted. They guy I bought it off was no other word for it, a bull****er. He said it was lowered and chipped but turns out two springs were snapped and the "chip" was an immobiliser. I bought another 1.7 engine and fitted it myself, plugged it in and turned it over and it started first time but it revs to 4k+ everytime and then drops back to around 1k and idles really lumpy and misfires. I changed the spark plugs and it ran a little smoother but still lumpy and it still misfires. I didn't put the uprated cams into the new engine as I just wanted it up and running ASAP but a mechanic told me the ecu will be set up for the uprated cams rather than the standard so it will be trying to run something that isn't there basically. Also when it is idling lump there seems to be a popping noise coming from the intake manifold/throttle body area, any ideas what could be causing these problems? If I bought a new ecu and loom would that make a difference or am I fighting a lost cause here? Any suggestions are greatly appreciated!
Scott

[happy-kat]

Hi
You sure it is chipped thought you first wrote it turned out it wasn't.
Try cleaning the idle control valve.
If it is running rich and lean lumpy then it could be the HEGO sensor, have you connected onto the ODBII port to read any errors.