Thanks for clearing that up. Did searches about the 'low oil pressure when hot syndrom' in the past and found a few comments on going for the cam bearings first.
I like the idea of main or rod bearing replacement better - it's seems easier to do and with the engine in place, according to the shop manual and a private message.
I believe my oil pump is good, because I changed it years ago with no change in pressure.
Around town the pressure stays up, but when I go on freeways or climb hills (especially in the hot summer around here) the oil pressure drops and stays down until the engine gets a long rest.
Any specialty tools required for replaceing main and rod bearings?
