'92 Nissan 4.2 Turbo varying oil pressure
 

:DHi all,
Love my Patrol, towed a van all over Eastern Australia and up to the top of Queensland recently without a hickup. But I'm having problems with oil pressure staying constant. Sometimes it remains where it should be, about 4 on the oil pressure gauge, and at times it will drop to as low as 1 or 2 even though I keep the revs up.
Change oil and filters every 5,000 kms, use Valvoline Super Diesel and Ryco filters.
Any suggestions would be great
Don