high oil pressure then drops down when idle

hi i have a 92 isuzu rodeo 3.1l 5 sp, 156000 miles....this morning on my way to work i was on the highway going about 60, and i noticed the oil pressure guage was maxed out, the guage was reading at 110, the normal range for my car is around 50 or 55,once i got to work and stopped the car, the oil pressure went back down, every time i step on the gas pedal the oil pressure guage goes up with it, i checked the oil level and that seems to be ok, i know that some people have recomended checking the oil sending unit, and the pickup screen, (which im going to do momuntarilly), ill prob change the oil and filter tomorrow,but is there any other ideas to what might be causing this??? also should i use the sea foam stuff on my engine, or will it just make matters worse loseing up stuff?? how much does it cost??

thanks in advance to anyones help

Thats interesting where the pressure goes all the way up, when most others get the zero during warm idle...Let me know if you ever change the oil pressure sender and update us....

I ordered the Haynes service manual for my 93, since I also have to swap out the OPS on mine too. Its in the mail. I will try to post up some update pics. I wish I have some bandwidth for a website for 1st gen Rodeos though.

If you have never added a product like seafoam to your oil i wouldn't do it. Change you oil and change it again in another 2k.

sea foam costs about 5 bucks/can