I have a John Deere 7220 tractor problem this decelarate tractor RPMs when operating. The local tractor technician cannot find a code for this problem or no remix for the problem. It has been going on for a year. I have pulled the trotlel back and pushed it forward and this does not help.
Check for any fuel leaks or restrictions and install a clear hose between the tank and the pump to look for air bubbles in the system causing low fuel supply pressure. If the engine runs smoothly but there is no throttle response, then the problem is more likely electrical than fuel delivery / mechanically related. Check the throttle position sensor and harness for problems, as well as the engine speed sensor harness and speed sensor. If ok, then the JD service advisor software should be connected to monitor live data for your throttle controls to determine if it is:
- a calibration problem,
- software / ECU update problem,
- harness / sensor problem, etc.