[JT58]

Is it normal for the RPM’s to fluctuate on the highway in 8th gear going a steady speed, flat surface- say 50, 60 or 70 MPH? I notice on mine that the tach, the RPM’s will raise and lower by 100 or so RPM when I am at a perfectly steady speed holding the gas pedal steady. The tach will go up and down every say 10 seconds- up 100 RPM, then down 100 RPM. I am guessing that it is 100 RPM, it could be 150 or 200- I see the needle move and can feel the engine RPM's raise and lower.