have you looked at data on a scanner and watched to see if your mass air flow, IAT, and TP sensors are working correctly befor, and after the problem starts. Theres not much left to check.

 

YOu might have gotten a bad fuel pump.

ONce the pump heats up it starts fucking up

 

Test plug wires for resistance. They should all be close.

 

yep that shit happens all the time

 

Yea thanks for all of the help. I am going to go catch a swell and then I am going to go and try a few of those things posted this afternoon. I will keep you all updated.

 

I agree with the plugs and wires first. the midle plug of the driver side is a bitch to replace. alot of times it does not get replaced, do to the fact that the steering link runs right in front of the plug. The link is very easy to disconect ftom the steering gear box and see if the plug is messed up.

 

i cant see it being plug , or all the plugs or that matter if it runs perfectly then 10 min. later has problems.

 

jeb when you bought the fuel pump did it come with a new plug? If so did you swap it out. I have seen this many of times come through my shop.

 

I can see that, but a quick test with an ohm meter will rule them out. They can run fine until they get hot, or good at low RPM then shitty at higher RPM. You said it bogs real bad at 3/4, does it feel like the tranny is slipping or bucking? Those are also signs of bad plugs or wires. Its amazing how simple things are sometimes, they just dont seem obvious.

 

I had a 1996 blazer with 4.3 also. It started idling rough then, proceeded over time codes like P0300 random multiple cylinder missfires and also P0171 lean condition. Later I then discovered a TSB for simptoms. Tsb was to replace lower intake gasket with updated one from dealer.