I have a 1991 chevrolet c1500 with a 5.7l engine. It will not idle unless I push the accelerator pedal. I have replaced fuel pump, rebuild the TBI injection throttle body, replace IAC, MAP, Engine Coolant Temp sensor, oxygen sensor, EGR and spark plugs other that that, the truck runs amaizing and sounds good as long as I keep the pedal depressed. It starts every time but does a few seconds after with the accelerator pedal depressed. I'm open for any advice. No check engine light.