My 97 2500 4x4 auto , once in a while the tach bounces around for a few seconds then the check engine light and gen light flashes for a sec like the truck wants to dies but it never does and it doesnt surge.What is happening- crank sensor,shut off solenoid?Maybe alternator?I doubt it because I get good voltage,the truck never overheats and has great power.I have also noticed it shifting in and out of overdrive a few times.Any suggestions,I've heard that there are some wires to wrap some foil around to stop the o/d problem

 

My first guess is that you have a bad ground somewhere.

 

What Bill said or a bad connection on the crank sensor wiring.

The TPS is more than likely the cause for the OD issues. There are several fixes to help that problem. Shielding the wire may help some but you probably need ot check the alignment/adjust the TPS for the correct voltage. Search this forum for "TPS adjustment" for detailed information.