1999 Pontiac Grand Am Acceleration Problems

Tiny
PRES1362
  • MEMBER
  • 1999 PONTIAC GRAND AM
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 120,000 MILES
Pontiac Grand AM GT

Problem:

Whenever I push down my gas peddle all the way, the car stops accelerating. This problem occurs at any speed whether on the highway or in town. However, if I accelerate by pushing my peddle down only part way, I have no problem. I've had this problem for over 1.5 yrs. Now and the fixes I've gotten haven't worked. The "fixes" over the last 1.5 years include:

-Complete tune up, catalytic convertor, oxygen sensor. 2 weeks ago, my car broke down twice b/c of a bad alternator and battery, I got both replaced. Again, I've had the acceleration problem for over 1.5 yrs, but it's never been this bad. It got much worse it seems after I got my alternator and battery replaced (but I don't see any connection).

-More info: When I push the peddle, the engine can rev up to over 4,000 rpms, but it slowly rumbles down if I push the peddle down all the way, and as it rumbles down it stops gaining any speed (whether I'm going 30mph, or 70mph, it doesn't matter.). Also, the gears shift smoothly and the check engine light is not on and hasn't been on. Also, when accelerating with the gas peddle down maybe 1/2 of the way, the engine smoothly accelerates past 2000 rpms smoothly but around 3000rpms, it seems to struggle a few times and then continue to go to higher rpms. Also, the car revs fine in neutral.

-Update: Service Engine Soon Light came on today but then went off after an hour of operation.

Any help would be great

Thanks !
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Monday, April 19th, 2010 AT 8:46 PM

3 Replies

Tiny
RASMATAZ
  • MEMBER
Hi pres1362, Welcome to 2carpros and TY for the donation

SES light coming on have the computer scanned for codes there's a problem within the engine management system this is your starting point of diagnosis finding out what's causing the SES light to come on and get back with the codes so we can continue to assist.

Or you can check the throttle position and manifold absolute pressure sensors to include a fuel pressure check.
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Tuesday, April 20th, 2010 AT 4:23 PM
Tiny
PRES1362
  • MEMBER
I had a diagnostic done on it, it was P0101 (MAF sensor). But at the time of the test, the SES light actually turned off. It came on again though and has stayed on, so hopefully there aren't any new errors. I'm taking it to the garage tomorrow. I'm just dreading hoping it has nothing to do with the Transmission.

Thanks again-
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Thursday, April 22nd, 2010 AT 2:50 PM
Tiny
2CARPROS LINSEY
  • MEMBER
Thank you for using 2CarPros. Com. We appreciate your donation and look forward to helping you in the future.
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Wednesday, April 28th, 2010 AT 11:43 AM

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