my oil pressure at idle seems to bounce around, it varies between the first line and 40. I take it the first line is 20 psi. is this normal? I don't remember it doing this before. under normal driving rpms its right at 40 constantly, so I don't think its a loose wire.

what can I check?

 

The sending unit may be starting to fail.

Nick

 

anyone know the easiest way to test it?

I was thinking of getting some kind of other gauge and hooking it into the other port on the filter housing. will this work?

 

thats the best spot to get at it ,and its 1/8 pipe

 

I agree on the sender. Mine did soemthing like that too. I was worried until I hooked up the mechanical gauge to the same port. Also found that the electrical gauge is still way off, even with a new sending unit. My pressure at hot idle is 40, as measured with a mechanical gauge, but the electrical gauge reads 20.

Chris