I have a 2006 diesel. I just noticed yesterday that when my truck would idle the oil pressure gauge would go to zero. The check gauges light kept dinging. Once I accelerated again it went back up to normal. this happened over and over again stop light to stop light. I checked the oil, oil level is fine an no leaks. Any ideas?

Also 2007 dodge 3500 diesel- when I have the cruise set and I go down a hill with the cruise on the truck starts jerking so bad you have to turn the cruise off. If you lightly push on the go pedal while going down hill it doesn't do this. seems like when its under a load it doesn't do it. Only with the cruise on and not under a load. Any ideas on this?

 

Sound like a possible bad oil sending unit. Put a real gauge at the filter head to be sure. The oils pressure gauge in the dash is pre-programmed to read whatever, at certain temps, rpms, air temp, etc. Below 6 psi of pressure, the gauge will read zero.