i have a 2000 grand cherokee 4.7 v8 I've owned it for about a month now and have always noticed that the oil pressure stays the same, around 65 psi according to the guage even when hot at idle or cold i changed the oil the other day and had the key on engine off to record the mileage down and noticed that it was reading around 65 psi with the key off any ideas what could cause this? thanks

sounds lke a bad oil pressure sensor. you shouldn't get a reading from the guage with the key ON engine OFF.