Hi All
I have been having a problem with a 95 3500HD 2WD with a 454 & auto trans. The truck will start and run fine up to about half throttle then it will sputter and backfire and run real bad. If I take the air filter off and rev the truck up at half throttle it will start acting up and the fuel injectors will spray and stop like they are being turned on and off very quickly.
So far this is what has been done to it: 2 rebuilt distributors,Distributor cap, rotor, spark plugs, Ignition wires, coil, fuel pump and strainer,fuel pressure regulator, throttle position sensor, injectors, ecm. All made no difference.
I have become so frustrated with this truck that I took it to a local repair shop and they have had it for over a week and can't find the cause of the problem & are running out of ideas as to what to do to it. The service engine light is not being set and there are no codes.
Any ideas will be welcomed as I am out of them.

Thanks in advance for any help anyone can provide. Al