Different Oil Pressure, Bad Gas??

I just got a 4.0 out of a 94 ZJ with 120,000 swapped into my 93 XJ a few days ago. It's been running great since, with 50 psi of oil pressure at idle and when warmed up. Then last night, I put gas in it, from Fusion Oil Company, new no-name gas station in town. Usually I go to a bigger name one, but it was on the way home, and it was reasonably cheap, so I went there. Didn't notice anything on the way home, it only a half mile til home, but today, I drove about 20 miles. The oil pressure gets to about 45 when moving, and about 20 at idle. It also idles a little rougher than it has been. Could this be because of bad gas? Should I siphen it out and put in good gas?

Different gas will not make a change in oil pressure. Your oil pressure is well within the factory specs.

Alright. But why would my oil pressure change overnight?

How are you reading oil pressure? If you are going by the factory gauge then by all means it will change over night. If you want accurate readings, run a mechanical gauge. The readings you have are well with in spec just like old man said. The running rough could be bad gas. Just throw in some fuel cleaner and a few gallons of good gas and everything should be fine.

AARON