Like the title says I've been intermittently experiencing low oil pressure from idle after the Jeep has been running a while. It is a 1997 4.0 w/ 210k miles. In the last 10k miles or so I have new exhaust, manifold, 4 hole injectors, 62mm tb, cai, new sensors on the tb, plugs, distributor, wires. New fluids, etc...

Basically when I push the gas to accelerate from a red light or other stop the rpm's rev but the car doesn't start moving. After a couple seconds it will get moving and shoot forward. A few days ago I finally realized the oil pressure is very low while this is happening. Around 12-15 according to the gauge. It only drops that low if I've been driving a bit, never from cold start. The rest of the time the pressure is fine, only dips low once I stop. Anyone have any suggestions on what it could be?

Right now I'm leaning towards a bad fuel pump? I also have an issue with the fuel tank needle dancing around immediately after i fill up, and its the original pump so I think they might be related? Any help would be appreciated. Thanks.

 

first - check the oil pressure and fuel pressure both with mechanical gauges. I'd guess that both are fine.

 

^ What he said ^

 

^ What he said ^ x2

Then while you waiting, make sure to check your transmission fluid level. As your "rev up launch start" is a symptom of being low on transmission fluid.

 

I'll check it again, but it was good as of a month or two ago when I refreshed the fluid with 3 drain and fills. Would that make the oil pressure drop though?

 

What is oil pressure when you are doing 55 mph ?

 

I would have to look, but its usually around 50 psi while cruising at 45 mph, which is most of my short, daily commute.

 

Your fine, stop worrying about the low pressure at idle because that is not unusual on high mileage engines. My 4.0 drops to zero at hot idle....been that way for +70k miles.

 

Do you have any suggestions? I've noticed that is still does it with good oil pressure. Starting to think its tranny related again.

Checked trans fluid and it is a little high, could that be my issue?

 

Mine dances all over the place. Keeps me entertained while rolling on the boring roads.