2005 3500 the ect is surging when the truck gets up to temp. its not the stepper motors also does it on the edge cts. after about 20 minutes of driving the ntruck starts this. When the temp surges the desired and actual fuel rail pressures drop and the truck looses power. I have checked the wiring at the alternator and everything looks good and changed the coolant temp sensor. nothing has helped new feul filter and still nothing. should the plug for the temp sensor ohm out ground?