Have just purchased a very nice low mileage (40,000) Dakota Crue Cab 4x4. Have noticed that when town driving the Tack doesn't remain steady and I can hear the rpm changing up and down slightly. Can also hear it in the exhaust. Is this normal? Anyone have the same happening to your truck and if so what is causing it? Thanks

 

Jumping around 200 RPM or so? Probably TCC locking/unlocking. It may be normal, or, it may be a sign of a failing TPS......