I have a 1994 blazer 4.3 engine code W. it has a rough idle, like its randomly misfiring when in park. If I'm sitting at a stop light the idle is even worse. When taking off from a stop it hesitates and shakes a bit. Driving down the road at 50 to 80 kph it works great but anything over 80 it will kick and buck and lose a lot of power when I try to accelerate or go up hill. I have replaced the fuel pump and sending unit, the fuel filter, fuel line, fuel spider, all new plugs and wires, rotor cap and button and the tps sensor. The fuel pressure is good, 60psi at start up, at an idle it holds steady at 52psi but jumps back to 60 when its revved up. There are no engine codes shown any time I check. I don't know what else to do to it, I'm running out of patients and I need help. Thanks in advance for any help.

 

Could be a plugged cat

 

Sorry, I forgot to mention that there is no cat.

 

Take off your EGR valve and clean it.

 

That was the first thing I did when it started acting weird

 

What parts did you use for the plugs and wires/ cap/ rotor?

Still sounds like the EGR valve to me, maybe it was not cleaned enough, or there is some carbon in the intake valley for the EGR.