Having problems with a steady speed of 40-55mph bucking and jerking. Ive change the spark plugs, wires, ignition coil, tbs. also cleaning the maf and changing the cap and rotor. Plus the OD shift light indacator will flash than go out thanks

 

Anybody have ideas?

 

Those symptoms could be the ignition system or the transmission , i.e. torque converter problems. It looks like you have all the ignition parts taken care of. You did use AC Delco parts for the critical ignition parts? I will leave the transmission trouble shooting to the experts here.