Trans Problem?...jerking

Hey, I'm new to the forums so whats up

I have an '04 6 cylinder Alero with 28k miles...yes its sweet and practically brand new

But we have had it in the shop a bit with bad alignment problems (that took a while to fix), but I have had problems with the transmission I think because when I'm around 1000-1500 rpms the car just jerks back and forth..the rpms don't flutter at all though. It feels as if im lightly tapping the brakes and it might be that the car keeps trying to shift gears, im not sure.
I've read some of the other posts on this same subject but they seemed to do more with older Aleros...

To try and fix this problem i have replaced the fuel filter, spark plugs, air filter and used fuel injector cleaner...but I'm still not sure if its a tranny or fuel system problem...

This is very annoying but I dont want it to be wearing down my trans so I'm a bit worried, especially with a decently new alero.

Thanks for your help guys, and I must mention that I'm not too incredibly inclined with my general car knowledge (I'm just 16), so any help is welcome. Thanks again.

[steve-o]

i'd say take it to the dealer and let them worry about it

i had a similar problem and it was my MAF sensor. i have an 03 v6 and it fixed it. i still have a low whine when im driving though if any one could help with that.