Can you diagnose my problem?

Asked by Smed62 Sep 13, 2020 at 10:31 PM about the 1999 Chevrolet Silverado 1500 Extended Cab 4WD

Question type: Maintenance & Repair

95 Chevy k1500, 5.7 TBI.  200k miles,
started running poorly.  I’ve changed
fuel pump assy, filter, and pressure
regulator, TPS, IAC, air filter,
distributor, cap, rotor, wires, plugs
and the O2 sensor.  I’ve swapped the
injectors and the MAP but it still runs
bad.  Could it be the EGR? It runs
somewhat better if the vac line is
removed from the EGR but it idles
high.  Thanks

2 Answers

I have cleaned the throttle body. I replaced the idle air control valve and now it starts ok but after idling for 90- 120 seconds the idle speed surges and falls from 1200 to 500 rpm’s. I’m thinking maybe the ECU needs replaced? I’ve pulled out most of my hair and winter is coming too soon. Any insight would be greatly appreciated. Thank you, Smed62

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