Steves95Sierra

CRP, Mike C., & citydriver... Thank you ALL for your help! Just confirmed a bad cat -- while in gear at RPM, the internals will start rattling around like they're rotting away (first though it was just a noisy flange). It's not completely blocked yet, but bad enought to obstruct the exhaust. Muffer and tail were replaced about 11K ago. A brand-new high flow cat it is... Thanks again All! Steve. . ..

Excellent point citydriver! I'll pull the O2 sensor tonight (since it's forward of the cat) and run the truck up the street without it screwed in to see if that makes a difference. If it does, I'll have the exhaust system vac tested this weekend. Thank you very much for your help! Steve.

Hey ...FUN.., same problem here Mine - '95 GMC C1500 4x2, 5.0l (vin "H"), 2-point TBI, 84k miles (yep - only 84k) Here's what I see/hear... Very poor performance - slooow acceleration through all ranges, all the time (almost as if I'm too lean all the time - though starts fine) Occasional afterfire upon laying off the accelerator at cruise (and sooty tailpipe - too rich???) Occasional backfire/stall upon stepping on the accelerator from stop (from intake manifold - too lean???) Engine temp has been getting hotter than usual, though far from overheating Lately - when the truck warms up, it sounds like a body panel expanding - 'pop' (may not be related - but freaken weird) This is what I've done... replaced spark plugs & wires, replaced distributor cap & rotor, replaced in-line fuel filter, siphoned bottom of gas tank (gas looked fine - no water or junk to speak of), listened for fuel pump operation (sounds fine - energizes anyway), rebuilt top-end of throttle body (meter body - didn't replace injectors), replaced O2 Sensor (only have one), replaced EGR & Solenoid valves, replaced PCV valve, blew out intake manifold (three treatments with SeaFoam through PCV & dumped into t-body), tested throttle position sensor (checks good), timing checks ok. Now I'm just confussed... What am I missing??? (oh.., I should add - no OBDI codes returned) Any help is greatly appreciated...