GMC Troubleshooting Questions? Ask a Mechanic for Answers
Welcome, I'm Chris (aka Moose) I prefer to work when others don't, I am here around lunch and after dinner till after midnight.
Check and verify that the Fuel Pressure Regulator is connected. Also OHM test it to confirm the reading is 3.0 - 5.0 ohms.
Check the "ECMRPV" 15 amp fuse. There should be battery voltage at key on, engine off.
Check the air intake for a leak. Check the Mass Air Flow sensor grams/sec value with a scan tool. Should have 42-50 gram/sec at idle and over 420 gram/sec with the throttle at Wide Open Throttle. Check the Barometric Pressure sensor value with the key on, it should be near 100 KPA and close to 5.0 volts.
Monitor the ECT reading with a scan tool to see if it matches actual temp.
Let me know these results.
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Hello again Chris here,