got a 1999 blazer. engine blew . bought a 2000 that had been rolled over. drove it around to check it out.ran & started good. swaped out the engine &trans . used the wiring that was on 2000 engine. now it want start sometimes (most times) swaped out the steering column .fuse box, computor from the 2000. put on new netural switch to try to get running. fuel pump runs. have to use a remote starter to get it to turn over. worked on cars for over 40 yrs. what am i missing?