1999 Pontiac Grand Am Grand Am that wants to GO!

Tiny
GREENMEANSGO
  • MEMBER
  • 1999 PONTIAC GRAND AM
  • 4 CYL
  • 2WD
  • AUTOMATIC
  • 80,000 MILES
I have a 1999 Grand Am, it has been wonderful up until the past 6 months. I had just gotten the powerstearing pump replaced (twice) and my abs light likes to flash and beep at me. Although the main concern of mine at the time is on random days my car decides that it wants to GO! I"ll start it up and it will run loudly (a revving sound), then when I put the car in drive it 'jumps' in gear and I have to hold the brake down as hard as I can and when I release the break the car accelorates at a very fast rate. Also while my car is in 'this mode' i'll be driving down the road and let my foot off the gas and my car will keep going faster and faster. When I place the car in park it will rev up to about 3 and sound like a race car. I've tried pumping the gas hoping that it was just stuck, there is nothing under/or in the way of the gas petal. When it's doing this it accelorates very quickly and it is very hard to stop if you have to stop at a stop sign or light, you have to hold down the break as hard as you can, then when you let off the brake the car races off. If I let the car go after a complete stop it can accelorate upto almost 40mph in no time without touching the gas.
I had someone drive the car yesterday while it was doing this and they were just as confused as I am. This has happened once this week and it happened once last week.
If you have any suggestions i'd love to hear them! Thank you so much!
Do you
have the same problem?
Yes
No
Thursday, June 5th, 2008 AT 1:39 PM

3 Replies

Tiny
MERLIN2021
  • EXPERT
May be a bad throttle cable, or worn throttlebody. Remove the cable and start it operate the throttle by hand, see if it returns to normal idle. If it does, check the cable. Oh yea, throttle should operate smoothly! A worn out TPS may cause the throttle to stick as well, and a bad Idle air control valve. Thats bolted to the throtlebody as well. May have a chnk of carbon stuck in it, pull it off and see if it needs to be cleaned. Cleaning works about 50% of the time.
Was this
answer
helpful?
Yes
No
Thursday, June 5th, 2008 AT 2:20 PM
Tiny
GREENMEANSGO
  • MEMBER
Thank you so much for your help!
I explained the problem to a family friend yesterday (he's a mechanic) and he said that it could possibly be a vacuum leak. Does that sound accurate at all?
Was this
answer
helpful?
Yes
No
Friday, June 6th, 2008 AT 8:31 AM
Tiny
MERLIN2021
  • EXPERT
Usually vacuum leaks tend to lower engine RPM's and when large enough the engine idle can fluctuate and stall. Havn't seen it cause very high RPM's tho. But a good way to check for leaks is get a can of spray gumout, spray the vac lines and maniflod area, when the idle changes, youve found the leak! You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs! If that doesnt do it, you may need a new idle air control valve, it's bolted to the throttlebody
Was this
answer
helpful?
Yes
No
Friday, June 6th, 2008 AT 12:52 PM

Please login or register to post a reply.

Recommended Guides