dppercle6

I have a 2004 Chevy Silverado 1500 Z-71 5.3 V8. Reduced Engine Power displays across the cluster, and the check engine light is on. I've had this problem before, and it comes and goes. To temporarily fix this problem, I simply disconnected the plug that connects to the throttle position sensor. Usually after disconnecting and reconnecting, it runs fine. However, recently it just stays at the "Reduced Engine Power" and I've been traveling about 15-20 MPH and nothing happening when I press the gas pedal. I went to Auto Zone, and they tested for the codes. The codes read P0120 & P0220, both pertain to the throttle position sensor.

I bought a new throttle position sensor. The old sensor was connected with pop rivets. I drilled out the rivets, and bolted the new sensor on. I started the truck, and it is still doing the same thing. SO....I took the "new" throttle position sensor off, and put the old one back on. I started the truck up, and surprisingly it is running like normal. The check engine light is still on however.

Furthermore, a new throttle position sensor comes with a new wiring harness. I didn't change that out, but there could be an issue with the wiring. Also, if you buy a new throttle body, the throttle position sensor comes riveted on, BUT it doesn't come with a new wiring harness.

I'm unsure if I should change out just the wiring harness, or change the throttle body completely.

Please help!!

dppercle6

It's been a while since I've fixed the problem. However, for future readers, this worked for me..... All I did was change the throttle position sensor. I bought it from auto zone, and it came with the sensor & wire harness. I cut the old wire harness (about 3 inches from the connector) one by one (all 8 of them). I matched wire for wire, peeling the sleeves off of both the new and old wiring, connected the wires together with the included butt connectors, crimped it together, wrapped it all up with electrical tape, and then changed the sensor. The original sensor is riveted to the throttle body, I already drilled the rivets out (read the 1st post) & the old sensor was just bolted back on. I used the hardware included, bolted the new sensor on, plugged the wire harness, and WAH-LAH!!! The reduced engine power light went away, and it has never (knock on wood) came back on.

nauticstar87

Thanks for letting us know the fix. Someone out there could use this I'm sure.