2003 GMC Sierra reduced engine power

  • 2003 GMC SIERRA

Computer problem
2003 GMC Sierra V8 Four Wheel Drive Automatic 190000 miles

While driving, everything seemed okay, the reduced engine power message came on and the truck dropped down to a max of 1700 rpm.
New spark plugs 2500 miles ago.
Any thoughts as to where to look?

Do you
have the same problem?
Thursday, February 7th, 2008 AT 9:21 AM

1 Reply


Check/Replace the Accelerator Pedal Sensor. Check the harness for any wires pulling out of the plug. Also, there are two grounds that can come loose on the back of the block below each cylinder head. I believe they are ground G103/G104. Lastly there have been issues with wires and pins coming loose in the large connector that plugs into the throttle body. I believe the brown and yellow in particular. The part number is PT1572 or GM# 88986255. It is about $100. If that is the case you need to cut and resolder one wire at a time as all the wires are white on the replacement harness. I have heard that GM is not being very cooperative with people when addressing this issue. Hope this helps.


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Monday, March 3rd, 2008 AT 9:48 AM

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