what would cause 2005 grand prix gtp to not accelerate over 30mph?

Asked by Jan 12, 2014 at 12:31 PM about the 2005 Pontiac Grand Prix GTP

Question type: Maintenance & Repair

1 Answer

4,745

If the engine seems to be running fine, but won't go over 30, your ECU might be stuck in 'limp home' mode. This can happen quickly and for something as silly as trying to jump the car when it's already running. Try this: turn the key to the "on" position, watching the Service Engine Light (SEL) carefully. It should come on, blink off for a split second, then come back on and stay on. If you didn't see it blink off, then the ECM isn't working right. If the SEL stays on when the car is running, a code will be stored and you can find out the problem with any OBD (Pep Boys will scan it for free). If it goes off when you start the car, you'll need to dig a little deeper. With the engine running, tap gently on the ECM. If the engine runs rough for a second, the ECM is bad. Do the same test on the MAF sensor. I would also test your fuel pressure to make sure it's within manufacturer's specs. Last but not least, a bad ground can cause a lot of issues. Make sure the block ground is good and tight.

Your Answer

Pontiac Grand Prix Experts

  • #1
    Js08016
    Reputation
    4,370
  • #2
    Tom Demyan
    Reputation
    2,980
  • #3
    munron
    Reputation
    2,360
View All

Related Models For Sale

Used Chevrolet Impala
578 Great Deals out of 34,582 listings starting at $1,250
Used Dodge Charger
429 Great Deals out of 27,751 listings starting at $1,650
Used Pontiac Bonneville
516 listings starting at $1,799
Used Pontiac Grand Am
1,087 listings starting at $1,599
Used Ford Mustang
752 Great Deals out of 42,443 listings starting at $1,300
Used Chevrolet Monte Carlo
17 Great Deals out of 1,355 listings starting at $995
Used Pontiac G6
76 Great Deals out of 3,908 listings starting at $1,500
Used Pontiac GTO
9 Great Deals out of 459 listings starting at $5,995
Used Chevrolet Malibu
1,224 Great Deals out of 77,384 listings starting at $1,500
Used Chrysler 300
357 Great Deals out of 16,702 listings starting at $1,000
Used Honda Accord
1,047 Great Deals out of 62,123 listings starting at $999

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.