Recently rebuilt Chevy 5.3L will start and idle on its own, but it backfires. Also noticed fuel dripping down the drivers side exhaust header. Fuel pressure is reading right around 60psi, I removed the injectors on the driver side to test them individually and they seem fine. Any ideas or suggestions for what to check and what the cause might be? Thanks.

 

Is one of the injector o rings not sealing correctly? Keep a fire extinguisher close by if fuel is getting on the exhaust.

 

" I removed the injectors on the driver side to test them individually and they seem fine".
If the injs check out, test the inj harness. It may have the ground side shorted and the inj will go on static when the key is turned on.

 

Fix that FIRST. Then once it's under control, and there's that much less danger of BURNING THE CAR TO THE GROUND, we can come back and work on the other, far more trivial, thing.