I have a 91 RS 305 tbi auto. When you give the car more than about a quarter throttle at any time under 2000rpm it loads up and starts backfiring. I never had this problem before I did a tune-up. I have replaced plugs, wires, cap and rotor, fuel filter, air filter, and the crankcase filter. I am completly stumped and starting to hate throttle body injection.

 

most likely not TBI related. bulletproof. Wires mixed up?

 

sounds like ignition also make sure none of the wires are burnt

 

Did you adjust your timing when you changed everything. I agree it sounds like an ignition issue. Also, does it blow smoke when it loads up? I had a similar problem a couple of years ago when my CTS (coolant temp sensor) went out. Luckily it's a cheap fix.

 

So I found my problem. I had the number 2 and 8 wires swaped at the distributor. I also checked the timing to find it was set at 23 degrees advanced. The car runs great now. Thanks for all the adivce.

 

No problem, glad all's well.

 

How did you check your timing???? Verify that your timing is correctly set by disconnecting the set timing connector!!! With connector plugged together you'll see about 20 to 24 of total timing. By disconnecting the set timing connector ECM will set SES light - clear it afterward by disconnecting battery for about 30 seconds (ignition off, engine stopped)
//RF