I have a 94 k1500 that has a motor that is about to quit. Its been parked for awhile but I drive it up the street and back every once and awhile. Today I did that and noticed when it goes to change into overdrive or if I really get on the gas it looses all of its rpms then suddenly they will shoot back up and everything is fine. My question is would this be the transmission or the motor about to quit.

 

it could just be a shift solenoid.

 

how would I check the shift solenoid?

 

scan for codes.