mattlmw

I am having a similar problem with my 92 5.7 k2500. I posted looking for help a while back under a different user name, but found no good suggestions, or at least any that fixed the problem. Mine will not idle well after warm up, usually around 400 to 500 rpm, and if driving for a while it will go lower. My biggest problem is when the idle drops that low the oil pressure also drops. The engine was just rebuilt in May and nearly everything is new. Since then I have tested and replaced almost everything on the truck including the 02 sensor, ECM, TPS, MAP, IAC, distributor, rotor, plugs, wires, oil pump, cam, timing set, lifters, ECT sensor, Temp. switch, tested the knock sensor, exhaust system, PCV valve, cleaned throttle body, compression tested, cyl. power balance tested, stall speed test, Trans VSS (both), tested tach, thermostat, water pump, tested ignition primary and secondary system, installed positive and umbrella valve stem seals, turned crank, new cam bearings, new oil pressure sending unit, manually tested oil pressure with guage, tested every individual wire from engine sensors to ECM, new radiator cap, ran 15w40 oil to boost oil pressure, exchanged oil filter head gasket for an un-restricted gasket, new serpintine belt, new piston rings, new thermostat, vacuume tested, replaced engine ground straps, tested fuel pressure, checked injector pulse width, tested injector resistance, and recently took it to a dealer to diagnose which revealed no problems they could find in two days of diagnosis. I know that is a lot to read, but if anyone has any suggestions on where to go from here I am all ears. I have also tested the EGR system, checked timing, and re set the overhead multiple times.
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