I have a 2008 Pontiac Grand Prix that is giving me an error message of "reduced engine power." Why?


Asked by Jan 29, 2014 at 10:41 AM about the 2008 Pontiac Grand Prix

Question type: Maintenance & Repair

I was just driving to work one morning and the check engine light came on and I got the error message of "reduced engine power." I suddenly had not power when I stepped on the accelorator. My husband took it to Autozone to have the fault code read and said it had something to do with the accelorator and a sensor. What is he talking about?

5 Answers

Johnny Houseman

Your Mass Air Flow sensor became unplugged or unhooked. Rare that a MAF would go bad to where it would need to be replaced, but can happen. It should take care of the check engine light after being reset, if that was why it came on. Good luck! Johnny Houseman Finish Line Automotive Owner 616-299-3210

1 out of 1 people think this is helpful.
Norm Davis

Your car has a Accelerator Position Sensor which tells the engine computer how to adjust the timing and air/fuel based on where the gas pedal is. When the sensor or wiring harness goes bad, the computer doesn't know what to do and puts the engine into "safe mode" which reduces the engine power. This is what you're seeing. Get the pedal position sensor replaced, have them check the steering column and pedal harness connections as well, you should be okay.

2 out of 2 people think this is helpful.
Joel Ledezma

Had this issue with my 04 Grand Prix. When in park, I'd press the accelerator and it wouldn't get past 1300 RPM. When driving, we would have to take off very slowly after a complete stop and even then, couldn't go past 65 mph. Replaced the mass air filter, the computer, and pedal/accelerator position sensor. None solved the issue and the car would still show the "reduced engine power failure" thing. Finally took it to some dude that had a $6k computer error reader thing and it came up with the throttle bottle assembly. After spending money on all this other stuff we said why not, so we went ahead and changed it. It cost a little over $300 at the local auto parts store ao we went to a junkyard/you- pull-it place and found the car we needed. We took it off right then and there. It doesn't take but 10-15 minutes to get out and put back in. all you need is a 10mm socket and git r done!! Sparked up the car and BAM!! We were able to press the gas and it picked up right away. It's been working fine for a small trip now and looks like this fixed the problem!! It was the throttle bottle assembly. When we took the original one out, the gasket was totally worn out and looked pretty ugly. That may have been it but just replaced the whole thing. Good luck!!

1 out of 1 people think this is helpful.
Mark Gersberg

mine stalled out a couple of times and it would reset clock and day/date etc... my mechanic says gas pedal sensor..does that sound right? my car is at shop now...

1 out of 1 people think this is helpful.
Mark Gersberg

no power at stop and said reduced engine power ,, once going it ran o.k. but idle was rough

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