My car is hesitating and or backfiring through the intake when you floor it from an idle or when it is under load.What could this be? It is basically not driveable and i don't want to cause any damage from backfires.PLEASE HELP!!!!!!!All opinions or suggestions are welcomed!

Backfiring thorugh the intake, sounds like a valve isn't closing fully, might be wrong though. That sucks man.

My car is hesitating, stuttering, and backfiring under the exact same conditions as you. I feel it in the exhaust portion though, The backfires seem to "pop" right under my feet. I suspect ignition/fuel problems (spark plugs, fuel filter, or fuel injectors). Can anyone shed some light on this? I want to try to fix it over the weekend if its something minor (I can only hope)...

Try changing wires and spark plugs. When I first got my car it still had stock wires and was running sluggish and backfired (exhaust) changed just the wires and ran much better. I have yet to change my plugs.

I am pretty sure it is your plugs. I would check the gap on the plugs and ask around on how much everyone else is gapping at with your mods. I think NA's with mods should use one range colder am I right??

its most likely your wires. both of my 420as have done the same thing

Thanks for all of the advice everyone. I've got 80k miles and have never replaced my spark plug wires, so I'll try that this weekend. Just to be safe, I'll replace the plugs too.

Thanks a lot guys.I replaced my wires with some 5 core 9.5mm ones from a performance shop and now it runs just fine.The ones that were on the car were some cheapo Beldens that looked a little crusty......Now about that power steering whine..............

Well the weekend is over and the car is running great! I threw in magnecore wires and NGK plugs and the whole problem is gone. In fact, this even solved a prior "bogging" problem that I once blamed on the tranny. Thanks again everyone for the excellent advice.