This model is a late 7 series so it has the electronic throttle body like on the 8 series trucks. The problem we are having is it surges at idle. Runs fine with lots of power any other time. If you depress the throttle pedal just a little bit twisting thepotentiometer it will stop. We dont have the scan tool to check any sensor operation. Any help would be greatly appreciated. The unit starts fine and the propane converter is adjusted to start well. Thanks.