I have a 1995 with a 454 that was running fine...Then I hit a Bull with it.
After the body shop got done with it It is Absolutely Gorgous! But it wont run worth a crap. It acts like its starving for fuel & backfires when driving or under any load.
I have replaced the fuel pump,pressure regulator,02 sensor,MAF.TBS,ECM,& on & on..
I had it a a garage he got an 02 code & thought it was the ground,so he Braised a peice of hard wire from the tail pipe by the sensor to the frame. It ran like a new truck for about 2 weeks then same problem back. It has a 1 wire 02 sensor. I don't know if it was something he moved when he was looking @ the truck & it went back or what.
It also has a brand new Hi-Flow cat. New intake gaskets. I'm tring to remember everything as we have replaced a grocery list of sensors & such.
It doesn't have a NEW Throttle body but it does have a different one a freind changed out.
Any help would be much appreciated as I hate to PART OUT such a fine truck,but I can't drive it.

 

I know she took quite a hit hitting a bull! Check your ignition out, it is quite possible that the distributor cap could have smacked the firewall and got cracked. (if I remember right the '95 is TBI right?)

 

Yeah,a bad cap can cause it to run like crap. Bad plug wires can look good and be bad under load. I know an accident wouldn't make them go bad but how old are they?

You can spend lots of money shotgunning parts.