ok last night i went to start the car, didnt hold the key for quite long enough, so the motor didnt quite catch it caught for a few revolutions then backfired! thats normal its done it before when being skimpy on the key...... well i fired it up right after and now at idle it hunts very badly, idle goes from 1300 down to 500, its has a steady miss at idle.
while driving it will continue to miss until about 1/4 throttle. after that it revs fine and still drives just as quick when u go past 1/4 throttle. It has thrown a CEL but havent had time to check it.

Question? can a backfire change the timing? what else could a backfire cause?

i popped the hood once i was home and check for vacume leaks, and for anything to the naked eye that looked outta the ordinary. didnt find anything?

thanks very much, this is my baby and my daily driver

start by checking the plugs, is it throwing any codes? If it is just go get the codes checked.

Codes are getting checked tomorrow, I can't check the plugs today I'm working lol,can a backfire damage a plug? Or what other damage can it do to the engine?

I had the same exact thing happen to me. I had the car a week and didn't start it all the way till it backfired. i was freaking out. I manage a parts store and have access to a lot of tech advice from my regular customers. I have a great gm tech thats a regular. i explained it to him and he said it sounds like the m.a.p. sensor. I went home and checked it out and sure enough it blew the vacuum line off the sensor. The sensor is under the throttle body and is pretty hard to see. Check it out this is probably you problem.