CherockeeXJ

What could cause the oil guage on my instruments panel to drop to 0 when I'm idling in park? As soon as I throw it in drive and reverse and press the gas it jumps to 40. Also when I kick my AC on it'll drop to 0 and then go up and down up and down till it gets to 40.

Bustedback

The oil pressure sender could be the problem.

JWheeler

Possible sender problem. Put an oil pressure tester on it and see what it says.

CherockeeXJ

So you think it's actually not circulating and not the gauge?

Bustedback

The sender is easily damaged when using a filter wrench to remove the filter. Plus the oil hole in the sender is very small, it does not take much crud to plug that hole. Replace the sender, if you still have an issue, then screw a mechanical gauge into the block and see what's going on.

CherockeeXJ

How hard is it to replace the sender?

Bustedback

If just screws into the block right near the oil filter. Just don't over tighten it. See if the parts store has a sender socket that you can borrow.