today iv pulled my new engine out of my car to fit a new clutch it ran fine before i took it back out but now it seems to be hunting ... its fine for a few seconds on start up but then starts with the up and down ... iv checked for boost/vacumme leaks the best i can iv unplugged the airflow and it runs no better iv done the same with the throttle position and it just revs high until i plug it back in ..... anything else i can check or try? cheers