1991 Pontiac Grand Prix GTP is idling to fast

[Patricia42]

Hi I hope you can help me because no one else can, the problem I am having is my grand Prix is idling too fast but it doesnt do this all of the time, lately the battery is dying and it is a new battery it seems the lower the battery the worse the idling is. I can smell fumes from the car and it shakes when it is in park or you are stopped at a stop sign. would a short in the car do all of this because when I use my lighter the fuse blows, and the highbeams will not shut off so we disconnected them.

Please try and help me i have taken it four times to a machanic they cant fix it and it is costing me a hole lot of money.

[richtazz]

The high beam issue may be an out of adjustment dimmer switch. There is a rod that runs from the turn signal lever pivot to the dimmer switch that, when out of adjustment, will not push the switch all the way in. The battery going dead is most likely a short causing a parasitic draw. The idling to fast sounds like a vacuum leak. There is a rubber block near the throttle body with 3 hard plastic lines coming out. One feeds the fuel pressure regulator, one feeds the map sensor and the other goes to the HVAC and vacuum canister. Check these lines for cracks and repair any that are.

[richtazz]

I forgot to add that the GTP models with the 3.4 DOHC also had a lower intake gasket problem that causes a vacuum leak, resulting in a high idle. It's normally worse when the engine is warmed up.