The needle on my oil pressure gauge started trembling about 1500 miles back--at idle and at speed. Changing the oil and filter didn't seem to affect it one way or another. Replacing the oil sensor did affect it--it still trembles (plus or minus 5 lbs.) but it only shows about half the pressure it showed with the original oil sensor. Any ideas?

clusters are known causes. There is a tsb somewhere on this. Its probably your cluster steper motor in the gage that is going bad.

yeah, get the cluster tsb and contact your dealer. i had too much pressure when i first got my truck. it would peg out in the morning

Are their given numbers to go buy for oil pressure at idle and cruising speeds like 55 mph?