overdrive
 

i have a 1986 gxl that has overdrive. when i drive around the city and i get to about 50mph. the cars seems to run rough but when i put the car into overdirve it seem to smooth out. can anyone tell me what could be the porblem and if driving my car in overdrive all the time would be bad for my transmission?

The transmission will not be affected.

When crusing at 50MPH in 4th you will be very near closed throttle.
At that point the ECU will cut fuel to the rear rotor injectors.
This gives you a rough exhaust sound.
(It’s not sure if maybe you want to slow down)
This is normal if you are just slowing down some.

If it's happening at steady speed on level road, your TPS is slightly out of adjustment.