I have 2007 3500 with 5.9 cummins, the other day I had plastic melting smell followed by the check engine light coming on. The code is showing 0148. The truck runs fine other than being flat on acceleration. checked oil today and found fuel in the oil. While the truck was on the computer the fuel pressure was in constant fluctuation at idle. I believe the set pressure was showing 648 AND the reading were dropping to the 620s and spiking as high as 719. The computer was suggesting a possible fuel pressure sensor problem. Dose sound like a likely. Could a bad pressure sensor create a situation where fuel will end up in the oil. Where do I find the sensor and is there any way tell if it is deffinatly bad

 

The rail pressure sensor is on the fuel rail, near the rear of the engine if you have fuel in you oil you have injector(s) fueling when they are not suppose to, we had a cummins in at our shop that bernt the fuse box next to the engine compartment Maybe that plastic smell?. But it should be constant and small changes in PSI. Fuel Rail Pressure should be near 5000 PSI at idle, and 20-30000 while driveing.