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White Bluff, TN
If your 4.3 is a vortec version,it has a fuel distribution unit inside the intake plenium,some refer to this as a spider because it has 6 plastic lines,one to each cylinder. They get brittle from the heat of the engine and crack or break open. This is a dealer item and cant get it from most part stores. You may get lucky and find one used and in fair shape. The fuel pressure regulator is also part of this assembly,and can be the problem also. The diaphram can bust and flood the engine. To replace it you have to buy the entire unit or as I mentioned,find a used one. Thing to remember is,a used one may be as old as the one you have, so check it out and make sure the lines arent cracked or brittle.
when I start engine it surges bad. when I accelerate up to half throttle its okay, but more than that,it falls flat on its face and misses and backfires through the exhaust like its real lean.i unhooked the iac to stop the surge,but it wont idle cold. the weirdest thing is that it gets worse when its below 45 degrees. as the temp warms 50 to 60,it starts running good again. Ive replaced the mass air flow,map sensor,coil and coil wire,and the tps. Ive checked for vacuum leaks and I replaced the fuel pressure reg and the ignition module about a year ago. the engine now has 222500 miles and still runs strong except for this.
I would like to thank you for your time and helpful answers. My daughter bought this car without me checking it out first. Seems these cars came from the factory with alot of problems,(electronics,brakes,trans,etc.) So,thanks again and have a good one!
do you check the engine trouble codes with a pin or paperclip like the obd1 system like a gm vehicle? if so, which pins in the connector do you use? i also have a PWR light coming on now. any ideas on this?
checked vacuum lines,they seem ok. check engine lite is not on,but the coolant lite is. coolant is full in radiator and the reservoir. started black smoking, bad egr maybe?
whats causing my engine to rev up to 2200-2300 rpm for no apparent reason? still does it if i shut engine off and restart. then it will go back to normal,about 7to800 rpm.