My 2007 ram 1500 5.7 has a gascap display that will not turn off and the truck idles fines but has been surging in rpm at slower speeds and causes the truck to jerk. Seems to smooth out after running.
tighten the gas cap or it will suck air in causing the display to turn on.
Defective cap or a line failure in the evap system can cause same. Have you scanned the PCM for codes? If you don't have a scanner, any Auto Zone or Advance Auto Parts store will do it for you for free.
I did put a new cap and still on. My bigger problem is at slow speed the trucks RPM really jumps up and down. It idles good and seems to be smooth at higher speeds. Could this be a bad throttle control sensor?
Throttle Position Sensor can cause this as well as a dirty or sticking EGR valve. However, TPS problems usually set a code and illuminate the MIL or Check Engine light. Code can then be extracted with a scan tool.
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