coupla Q's

I have just bought an automatic '00 Pontiac Grand Prix SE. I've had the car for two weeks and I had to bring it back to the dealer 3 times already. First, one of my wheel bearings went and they fixed that. Now, the engine occasionally sputters and the engine service light comes on, the car makes a knocking noise when i turn the wheel hard, and the tranny kicks pretty hard when shifting from 1st to 2nd, and 2nd to 3rd. Anyone have any suggestions as to what could be wrong?

Check if the car is misfiring. When my car sputs and rough shifts related to the engine heistation and the SES come on usually is a broken spark plug cable, bad plug or coil.l

Well I took the car up to the dealer today, and they put it on their machine. They said the TCC(Torque Converter CLutch) code came on. So they took apart the tranny and said they were gonna replace the valve body and the valves, so we'll see how that goes...