2002 grand prix gtp transmission problem?

[thecrow1986]

when i get in and drive it has power but sometimes when im puttin the pedal down it will kinda stumble while or after shifting high gears. 220000 miles. tranny fluid and filter done every year. it is still fast but i dont like the stumble. maybe its something else? no engine light on

[tblake]

When was the last full tune up done. Usually a stumble at medium to heavy accelleration is caused by secondary igintion component missfires (plugs, wires).

[thecrow1986]

i did plugs and wires 3 months ago. ac delco parts

[tblake]

what part number on the plugs? Were they rapid fire delco plugs? the iridium 41-101's porcelin can crack easy when putting them in causing an issue much like you describe. Did the issue start shortly after you replaced the plugs?

[thecrow1986]

no the issue was there b4 and not a thing changed when i swapped them out. yea the iridium ones

[mutantenemy]

I would recommend checking your fuel injectors for proper function. I don't remember what their values should be but you should be able to find out on this site.

I have a 2000 GTP and had a similar problem beginning at about 100,000 miles and the problem continued for another 15,000 miles before I was able to determine the problem.

First I tried changing the plugs and wires, also with no improvement. After that I swore it was a tranny problem but held out because I've never had a problem with a GM tranny, even after over 210,000 hard miles on each of 2 previous GM's. Then finally the fuel injectors actually coded.

Doing research on the problem at this site I found out that the #5 and #3 fuel injectors typically fail early on the 3.8 L engine. In my case, at first the #5 injector failed so that was all I replaced. Two weeks later the #3 injector failed. So consider changing both at once to save yourself some trouble.

After replaceing these fuel injectors the car runs fine again. I use the GM recommended Iridium plugs with no problem. They do seem to run much better on Sunoco gasoline than Mobil or Hess. I don't have any Shell or Chevron stations around so I can't comment on them.