Hi I have a 89 300zx TT and i just done a engine swap recently because the old engine blew up and now most the time it wont go and when i do finally get it to fire up it backfires really loud and sounds like its not running on all cylinders, even when i do get it to start sometimes it idles and other times it will just die again. i checked which exhaust is backfiring and its coming from the left hand exhaust and the right hand one doesn't seem to have anything coming out of it at all. I installed a new timing belt and spark plugs when i put the engine in. i checked the spark of all the coils and took the crank angle sensor off to see if the injectors are pulsing, checked the wiring harness to the e.c.u. i can't think of anything apart from maybe i got the timing slightly off?? anyone got any ideas?? maybe its electrical??