Oil pressure question

I have a 1988 jeep xj with a 4.0. What is the oil pressure supposed to be on these babies. According to the guage it reads 19 all the time. But every once in awhile it drops while accelerating or at a stop. But then it will be ok for awhile.

sounds like you need a new sending unit. its located next to the oil filter adapter.

If you disconnect the wire from the sender the needle should go all (or most of) the way up on the Renix, If you touch the sender wire to ground, the needle should go all (or most of) the way down.
The contact strip in the back of the instrument module gets oxidized, this usually causes high readings.
If the sender gets a partial internal short (or low resistance) you get low readings.
All in all, the sender and the gage aren't a good indicator, hooking up an external mechanical gage will tell you what you actually have and then you can judge the true (or nearly so) oil pressure from your normal gage.
Mine habitually shows 10-15 PSI lower than it actually is. I usually just make sure the needle isn't pegged one way or the other and has movement. If the oil pressure gets too low the motor gets fairly noisy quick.
I've had the sender improve, just by taking it out and cleaning the hole in the bottom and spraying it out with brake cleaner.
Most every time I have the dash apart, I clean the contact strip for the instrument module with a pencil eraser and wipe it down with contact cleaner, to avoid future problems.

on my sunpro i get around 20 idle, and 60psi crusing