high idle and over heating

Asked by Jan 21, 2017 at 12:04 AM about the 2003 Pontiac Grand Prix GT

Question type: General

need some help here.
It's scary to drive this thing, need this fixed ASAP.
In Park and Neutral, my RPM goes up to 3900 and
sits there. Happens right at start up and RPMs
never go down even when engine is hot.
In Drive it goes down to 1800 and sits there.
In Drive, if I let go of the brakes - the car takes off
like a bat, due to unusually high RPM.
When I drive this car, my foot is constantly on the
BRAKES! .. not good at all.

WTH is the matter with this thing?
Is it an idle issue?
A vacuum issue?
Something else?
Please help. It now started to over heat to.

1 Answer

73,745

First thing you want to do is get the codes read. This will point you in the direction for repairs, but I suspect it is the Throttle Positioning Sensor, or the Air Idle Control Valve. Either they are unplugged, or it and the plugin are bad. Check over the engine all the plugins to make sure everything is connected, might get lucky and find something. Another problem on these is the intake manifold may be loose or bad gasket. Take a bottle of water and squirt it around the intake gasket, around the throttle body checking for air leaks. The rpm's should hesitate if there is a vacuum leak.

Your Answer

Pontiac Grand Prix Experts

  • #1
    Js08016
    Reputation
    4,390
  • #2
    Tom Demyan
    Reputation
    2,990
  • #3
    munron
    Reputation
    2,400
View All

Related Models For Sale

Used Chevrolet Impala
518 Great Deals out of 33,770 listings starting at $950
Used Pontiac Bonneville
509 listings starting at $1,799
Used Chevrolet Monte Carlo
16 Great Deals out of 1,319 listings starting at $1,950
Used Ford Mustang
711 Great Deals out of 38,301 listings starting at $895
Used Pontiac Grand Am
1,050 listings starting at $1,899
Used Pontiac GTO
12 Great Deals out of 473 listings starting at $5,995
Used Chevrolet Camaro
412 Great Deals out of 30,659 listings starting at $3,550
Used Chevrolet Malibu
1,123 Great Deals out of 71,678 listings starting at $1,896
Used Pontiac Firebird
9 Great Deals out of 781 listings starting at $2,500
Used Honda Accord
1,098 Great Deals out of 61,485 listings starting at $999

Used Cars For Sale

2007 Pontiac Grand Prix GT For Sale
70 listings starting at $2,400
2005 Pontiac Grand Prix GT For Sale
3 Great Deals out of 99 listings starting at $1,500

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.