When I'm at highway speeds my truck's RPM's rise and fall like they I'm revving the motor. They go up and down like 200-400 rpms. The truck is pretty much stock no tranny work ever done or any problems except O2 sensors that I just changed out, they didn't help the problem. Any suggestions?

 

Approx what rpm and mph is the truck at while suring? Is it more noticable by the tone of the motor or do you feel it. Mine surges around 45-50 mph w/ rpms at about 1200. I believe its the tc locking and unlocking while cruising steady. I've had tranny flushed and filter changed w/ no fix. Doesn't do it very often.

My plan is to get westers to alter the shift parameters so it doesn't lock up until 50-55 next retune.

 

How many miles on the truck? An egr valve will cause it to surge. At least it did on my other truck.

Brad

 

Yeah mine surges at about 1200 at about the same speed. There is 85k miles on it. Why would the egr cause the surging? You really dont feel the surging, but you can definitely hear it in the motor and see it on the tach.