I have just completed an engine swap on my 240 and when i went to drive it, it started to act up.... i will not stay started at idle and it runs like poo... if anyone has any sugestions then please let me no... i think that it may be a vacuum leak but i am not sure.

 

MAF sensor? could be a number of things......

 

ignition timing, no spark, pluged injectors, injectors pluged into the wrong harness, plug wires on wrong plugs. are you geting a check engine light cause if so you could check for codes.