I have a 2000 CTD 2500 . I have just started having trouble with the gauge . When I just turn the key and not start it , the gauge reads 40 psi .
After the truck is running the gauge goes up in pressure . After the truck runs a short time ,the gauge drops out no reading . I know it has oil pressure !
If I turn the key off and on a couple times and restart it works fine after that . I tryed disconecting the oil sender wires and then trun the key on and the gauge still goes to 40psi . I dont think it is the sendening unit . They are not cheep ot just replace to try . I was also told that may be , They need to reflash the computer . What does reflashing the computer do ? The truck is stock . The truck runs fine and the auto trans shifts good .

ANY ONE HAVE A IDEA ? :

 

testing for reply

 

If you do a search on here you will find the oil press sending units are not reliable and changing it usually fixes the problem.