My 1991 Accord has a issue where the rpm will increase and decrease about 300 RPM while at cruising speed in 4th gear. It almost sounds like the transmission is shifting but not quite. I have shifted from 4th to 3rd to verify that it wasn't accually shifting. One of my friends said possibly the throttle position sensor could be bad. I have no idea. Has anyone heard of an issue like this?

 

This is normal operation, the trans is going in and out of torque converter lock up.