Now_ I"m trying to fix another problem, every time I turn ON the the truck the gauge displays low oil pressure and stays there for a couple of minutes but after that works oK. I don't know how to check the oil pump, or should just buy a new one.

 

Change the oil pressure "switch" located on the oil filter adapter.
Good luck.

 

x2

If your pressure keeps dropping on the gauge and your not having any problems then it's gonna be this. Not to mention it's only a $7 part and takes like 10 minutes to change.

 

I'm driving a 2001 4.2 L and the dealership recommend 5W-20.
I live in a warm weather and people recommend a heavier viscosity like 10W-30 so i am confuse as what viscosity to use.

 

I run 10w-30 in mine and have for years. But either way you still need to change that switch or your guage will continue to do the same.

 

Thanks

 

Use the recommended weight.

 

Occasionally when i fire my truck up and its been sitting cold (in the 20s) all night the oil pressure gauge jumps between normal and low and the light comes on. if i tap the gas it usually jumps back to normal. this will go on for 30 seconds or so before it goes up to normal and stays there. Is this the pressure switch?