Here's the problem. When I punch on the gas from idle or below around 2800rpm the car hesitates and backfires. If I take off slowly it runs fine. It idles normal and it drives normal once it's going. I've changed plugs, wires and fuel filter. No leaks are coming from the valve cover because I changed that not too long ago also. I also put some fuel injector cleaner in Saturday and that didn't help. I've asked people and I've heard everything from timing, bad/clogged fuel injector, bad ignition coil, to a vacuum leak. If anyone can point me in the right direction I would really appreciate it.

its a bitch huh? that happened to me for the longest time, i couldnt even floor the gas pedal. What ended up being the problem is i had a wrinkle in my head gasket and i had oil leaking. i know you said you dont have that problem, but thats what was wrong with mine, sh*t sucks. my baby hesitates now when shes cold, maybe if you let her warm up a little...
hope this helps some,
Isaac