Why Is My Peterbilt Losing Power? This is a great question many things come into play of Why Is My Peterbilt Losing Power. Two simple reasons could be plugged Fuel Filter or a plugged Air Filter. If you have restriction gauges installed in your Peterbilt or Kenworth that is simple enough to see if they are restricted. Another Possibility on later model Peterbilt or Kenworth Trucks is that a sensor may be reading wrong, and it is in a Derate Mode where it’s cutting the power to the engine by 25% or more. This can be a little trickier to fix. If the CHECK ENGINE LIGHT IS ON, it will have a code set that will guide the technician in the general direction. This can take specialized software such as CUMMINS INSITE or DAVIE IV depending on whether you have a Cummins engine or Paccar engine in your Peterbilt or Kenworth. We have both CUMMINS INSITE and DAVIE IV software to use to find out Why Is My Peterbilt Losing Power. If it ends up needing a new Calibration File to fix your engine, we can reprogram both CUMMINS and PACCAR engine control units. We also have the electrical tools that we need to check your wiring harness and sensors to make sure they are reporting the proper information to the ECM. We also have ESA software so we can diagnose the chassis control units and reprogram them if needed. If you are experiencing a Why Is My Peterbilt Losing Power give us a call and we would be happy to diagnose the issue for you.