Rebuilt my v6 about 5 weeks ago and brought it back to have the valves tuned twice now and the motor mount was replaced this week but my mechanic found a messed up fuel injector so he changes the and now my oil pressure is low, my car stalled out and isnt starting well. it cranks for a fewe seconds before actually starting and before this week when the injector was changed it started up right away in less than 1 second and never stalled or dropped oil pressure. WTF is wrong with it?!?!