98 tahoe 5.7

[haredog]

I have a 98 5.7 vortec, that just recently had problems starting, I hooked it up to a scanner and everything says its alright. Well not entirely, I had several misfires on a couple of cylinders. I replaced plugs and wires no change. Checked timing and I was within +/-.2DGRS OF 0, reset to exact 0. Its as if the starter is fighting the timing. And when or if I do get it started it backfires (or pops) within the exhaust system. I've heard the distributors have been problems but don't know what or even its that true. Fuel pressure is okay, no leaky intake gaskets that I can tell. Any ideas?

[abaird]

Ignition timing on these motors is completely controlled by the computer. If you start turning the distributor you will mess up the base timing and that could definitely cause running problems and probably turn on a SES light. One thing I have noticed with my 97 k1500 that I used to have is that the dist. cap was prone to getting moisture in it and that would cause misfires.

[UncleBob]

as abaird said, timing is completely controlled by the computer, you can spin that distributor around 180* if you like, it won't change the timing. But if you go too far it'll throw off the cam sensor (in the distributor) and the cap posts won't be lined up with the coil fires

If you use a scanner thats capable, it'll tell you the crank to cam sensor offset, and using that you adjust the distributor to get the offsets zero'd

That may or may not be your problem, but if you've been messing with the distributor, you should definitely start there