transmission

i have a question for anyone that can help me out. when i switch gears it jerks a little but and im not sure why it does this. also my check engine light is on but my car runs fine and everything, also i was wondering how much a tuneup would run me. If anyone knows any answers feel free to let me know either here or email. thanks

Tune-ups will depend on how much you actually do, and how much of the work you do yourself. A basic tune-up is always a good idea. Start with plugs, wires, distributor cap and rotor button (if it's an N/A), change all the fluids, and the list keeps going. If the check engine light is on it means you have stored codes, to pull them follow the instructions here...
http://www.cygnusx1.net/supra/techtip/engineerrorcodes.html
There's alot more helpful info on the Cygnus/online TSRM site...
http://www.cygnusx1.net/supra/techtips.html
When and how much is it jerking? Enough to throw you around the car? How does it do it if you slip the clutch alittle, or only when you drop it? The 7m's have a sprung clutch stock so it will allow alittle more slack in the drivetrain, somtimes making it jerk alittle bit. If you want a rough ride/shift though try using an unsprung clutch :p . There are a few other things it could be but we'll start with that.

his car is a supra auto with a 91 or 92 engine in a 88....i told him it was the tranny