I have a 2004. 5 Ram 2500 on which I installed a Quadzilla Commander a couple of years ago. Lately, the boost pressure readout was "all over the place" and now it reads 8 lbs WITH THE ENGINE OFF and 8 lbs and up with the engine running. How can I determine whether the fault is the factory sender or the Quadzilla? (The wire to the quadzilla splices into the factory wire from the sender, and it's (now) a soldered connection.