Just got a 1999 Jeep with a 4.0L, 223000 miles, oil pressure was dropping a bit, I put a high volume pump in, now at idle it starts at 40psi then drops to about 20psi where it stays even while driving. Should I be concerned about this ?

 

Should be ok...

Is it using or burning any oil? Smoking? Have you done a compression test?

 

not burning or using any oil {yet} compression is good. hopping it will hold on till I can do a rebuild on one to drop in.

 

Those numbers are nice, nothing to worry about.

 

Do you mean it's staying at 20 psi even during driving, or just at idle?

At warm idle, anything above 13psi is still within spec, but at 1600 rpms or more you should be above 35psi

 

Have you verified that pressure with a mechanical gauge? Or are you going off what your gauge cluster tells you?

 

I've been having intermittent low oil pressure at idle with it dropping to zero and the "check gauge" light on. Today I took the oil pressure sending unit off and cleaned it. Oil pressure is now steady at idle.

Not saying this will fix your issue but it's worth investigating.

 

yup verify with a mechanical gauge

 

Thank yall,, I will verify with a mechanical gauge, and clean the sending unit, thanks again.

 

Let us know what the mechanical gauge reads.

If you buy a sending unit, I recommend you buy a Mopar unit from Jeep for the best reliability/accuracy/mating with your factory gauge.

Good luck!