i was coming back from taco bell 3 mins away from my house and just driving down a back street doing 25 mph at most oil pressure drops to 0 and comes back up. did it again a min later. what would cause this? thanks

 

crap in the sending unit maybe?

 

i will give it a shot tomorrow. thanks
anyone else?

 

Jim this is a common problem - my 98 12V has been doing this for awhile now. Usually, the sender just craps out and you have to replace it. I installed a mechanical oil pressure guage in the cab because I was worried and hadnt replaced the sender yet. My oil pressure ranges from 30 psi to around 90 psi (winter months with 15W40 oil):

https://www.dieselbombers.com/12-val...-pressure.html

Anyway, if you have oil in the crankcase, there is a VERY good chance that the problem is the sender. The Cummins p/n should be: 3923200. And the sender can be seen here (OIL PRESSURE SENSOR):