My 94 formula sometimes has an issues with the oil pressure gauge. After driving for awhile every once in a while the gauge will drop down to 0 psi only for a sec than comes back up to around 20 psi @ idle. It only dose @ idle never when driving. I'm thinking the sending unit is starting to go out, what do you think?

 

Only sitting at idle, or just as you stop?

 

most of the time it does it after I come to a stop and sit there for a minute. But like I said it doesn't do all of the time. And it's only after you drive it awhile, I checked the oil it's full, but needs changed.