Bucking up hills? [Archive] - GrandAmGT.com Forum


View Full Version : Bucking up hills?

11-06-2007, 09:48 AM
Hey recently i had noticed that my 99 grand am gt when going up hills will begin to buck, although i'm not pushing it any harder. It happens basically between 2000 and 2500 rpms. I assumed it was from the k+n cold air intake i put on it, maybe tricking the ecu into thinking it needs to shift when it doesn't, or maybe an improper fuel to air ratio. I also had crashed my car a year prior, which also could be the cause of this problem. It reminds me of the traction control system, how you can give it gas and it just doesnt feel like your accelerating, also my security light and wheel pressure lights are on....any thoughts?

11-06-2007, 04:03 PM
when was the last time the plugs and wires where changed?

11-07-2007, 10:23 AM
last summer, new wires and 6 new platinum spark plugs

11-07-2007, 10:42 AM
Happening around 40 MPH? Last I heard the stock PCM had problems around this speed. It would up and downshift quickly as if it was confused as to which gear to use (correct me if I'm wrong).

11-07-2007, 11:47 AM
ooo im not sure what speed it happens at but i will be sure to check that next time i drive somewhere, i hope its a recalled part

11-07-2007, 04:05 PM
doesnt the torque convertor lock up at 40?

11-07-2007, 10:03 PM
Not sure exactly... It's just the closest situation as to what brockfn13 was describing. :) All I know is the problem at 40MPH can be fixed with a tune or custom PCM.

11-08-2007, 12:29 PM
im looking into getting a new pcm thanks, well see what that does for me

11-08-2007, 01:14 PM
almost sounds fuel related, what about when you go WOT does it lose power. Could be something like a TPS. My $.02

11-10-2007, 09:24 AM
almost sounds fuel related, what about when you go WOT does it lose power. Could be something like a TPS. My $.02
WOT? im sorry im clueless

11-10-2007, 09:36 AM
Wide open throttle

11-10-2007, 12:17 PM
nope when i open it up is when it goes away, also i checked and it is not speed related it happened several times at differing speeds, im looking into getting a dhp pcm do you have to run 91+ octane on it because its up over 330 around me

11-10-2007, 01:40 PM
nah, just have them tune it for 87. or go thru MP racing, he can custom do what ever u want and he's alot cheaper as well

------> http://www.mpracing.org/store/index....d&productId=92

11-10-2007, 03:46 PM
Sounds to me like the torque converter is locking and unlocking as someone mentioned. If you go to about 1/2 throttle when this first starts happening it should stop completely.

The converter clutch does lock up around 40mph and a slight grade will cause the transmission to lock/unlock it while cruising to maintain speed. Its normal and yes a tune could take care of it but its nothing to worry about.

Mike Jung
11-10-2007, 06:25 PM
Another good reason to put it in 3, instead of D.
When driving up & down steep hills.