Timing issues?
 

I have a '99 Suburban 1500. We had a dead battery, but after charging it we went to crank it and it would not start. Several attempts later it backfired (something flew out of the tailpipe when this happened). It still will not crank and according to the codes it is misfiring. They checked the coil and it's fine. After you stop turning it over it still attempts to spin on its own for a few turns (it's exactly what would happen if you had bad gas and shut the car off and it attempted to run after being turned off. I'm saying the thing jumped time, but hubby disagrees. Any other ideas?

Ang :)