04 Grand Prix GTP hesitation/bucking

[TMBT1989]

Guys im really needing some help. I have an 04 GTP, when Im on the HWY cruising 65 when i start to go up hill the car starts to hesitate and has a bucking feeling. It will also do the same thing if Im cruising @ 45MPH and slightly accelerate. The car has 75K miles on it. I have changed the transmission fluid and filter but is still doing the same thing. I understand that this topic a fairly common problem. So if anyone has the solution to fix this problem I would greatly appreciate your imput. Thanks

[dsmuts]

Cel on? Try plugs and wires and clean your maf

[TMBT1989]

What do you mean cel on?

[Fivefingerdeathpunch]

"Check Engine Light"

[TMBT1989]

no its never been on

[Below Average Joe]

have you ever had it scanned?

[TMBT1989]

No i haven't had it scanned. Im looking for someone that is having the same problem as I am. I have read forums and forums over this topic but no one really said what they did to fix the problem.. Also its not a constant problem. It may do it a couple times a week, then not do it for a week or so. Its very strange.

[Below Average Joe]

i would go have it scanned at your local auto parts store to see if it is throwing any codes

[TMBT1989]

Thanks for the help!

[Below Average Joe]

Knowing what the codes are (if any) will help us out a little bit more. Have you tried cleaning your MAF and your TB? If not, when you are there having it scanned, buy some TB cleaner and MAF cleaner. TB will look clean but it will be filty on the inside if it has never been cleaned before.

[dsmuts]

Sounds like a mass air flow sensor issue. Clean it and also clean the throttle body while you're at it.

[Linebacker]

sounds a bit off from what i had, you can read my horrible story here

http://www.grandprixforums.net/showthread.php?t=67871

Coming from someone who went down this long expensive road if i were you i would clean the MAF, see if it helps. If its still there you can try replacing the MAF, otherwise maybe try the PCM update that fixed my car, you can have it done at any GM dealership and its under $100

Quote from my thread

"FINALLY FIXED So after close to 6 months of dealing with this issue its finally gone. spending over $4000 on sensor changes and any other "guess" to what it could be, plus a full transmission rebuild...turns out the problem was the TCC sticking which was corrected by a simple PCM upgrade. Reference number 04-06-04-078, Anyone with similar issues just drive down to your gm dealer and get them to check for any updates for your PCM and put them in. If you go to a transmission shop like i did, you might end up paying for a rebuild you probably did not need."

[primem]

no its never been on

the tcc will come out of full lock up at during the conditions you describe, it may be shuddering at it pulse width modulates out of full lock. This will not set any dtc's.

does it go away when you accelerate harder?

[TMBT1989]

Yes when i accelerate hard its fine. It will do it when im cruising at 45 mph and 65 on the highway. It only happens when I lightly accelerate. At hard throttle its fine..

[Robxstone]

My 07 has been kinda doing that since when I bought it new... its only a 4 speed transmission... usually when your in 4th going up a hill..eventually it down shifts on its own to increase the power.. usually I just give it more gas before it does this.. seems quite common even in a car that has been babied from day one.

[primem]

there no mistaking a tcc shudder and a delayed downshift. the shudder can occur more than once