[ptc1625]

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