1995 GMC Suburban rough idle, missing, and hard start

1995 GMC SUBURBAN
20,000 MILES • V8 • 4WD • AUTOMATIC
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HEAVYCHEVYGUY
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350TBI reman motor. w/20k mil. heads on the reman motor were junk went bad after only 20k. They were replaced w/ edelbrock performer heads#60859. The motor also has a mild edelbrock cam # 3702, edelbrock intake # 3704, edelbrock performer chip, shorty headers, high flow magnaflow cat, and a flowmaster catback muffler.
After installing the new heads and cam I noticed rough idle under load at cruise/low 800- 1500 rpms (it actually ran rough at/around 800-1500 rpms and cruising b4 the heads were replaced), surging at the light and at /around 30-45mph, missing in a couple of cylinders, back fire at the throttle body, black spark plug threads and tip, and hesitation when shifting from 1st to 2nd gear.
In attempt 2 fix the problems I retorqued rocker arms, reset the timing to 0 degrees BTC with the brown connector unplug (my old skool mechanic buddy set the timing at 12 degrees BTC), rechecked recommended plugs (champion r12yc) 2 see if they were all the way in, changed ignition wires( ac delco 7mm silicone), and accel distributor cap and rotor. I also changed the egr valve, it was setting codes B4 the other parts were added. I noticed b4 the heads were installed, when examing the intake the egr air passages were completely block by carbon build up. I clean the passages up good b4 I reinstalling the intake. What really puzzles me is with all these symtoms no codes have been set??? What am I missing???
Jul 24, 2009 at 9:33 AM
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JACOBANDNICKOLAS
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This is a tough one with all the new parts. Like you said, it is interesting that no codes have been set with a random misfire happening. Have you checked fuel pump pressure? Has the fuel filter or pump been replaced? I wonder if it's starving for fuel.
Jul 24, 2009 at 10:43 PM
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HEAVYCHEVYGUY
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Sorry I forgot 2 mention I did actually change the fuel filter, it was the first thing I changed after 1st noticing white smoke from the exhaust. I was hoping that the white smoke was coming from a bad filter or water down gas, but it was actually the heads gaskets on the old heads. I wil check the fuel pressure today. Where is a good place to hook the pressure gauge up???
Jul 25, 2009 at 8:09 AM
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JACOBANDNICKOLAS
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Here is the how to for checking fuel pressure.

https://www.2carpros.com/how_to/how_to_check_fuel_pressure.htm
Jul 25, 2009 at 8:20 AM