What type oil 1998 jeep wrangler? - Wrangler Jeep Cars & Trucks

rear main oil seal

Check timing. Timing belt/chain.

Between 20-30 psi at idle.

SAE 70W/90W GL-5 Gear lub.

oil pressure sensor may be bad

just jack up the frame and let the wheel hang or on a lift and should come right out or wiggle it out

Wire on oil sending unit may have fallen off or sensor itself may have gone bad. Check both. If engine has no tapping noises, likely it's not a pressure problem.

There are several things you can do if you haven't done so already, Check voltage at ignition coil, as soon as the engine starts to turn over there should be voltage. If not, the crank sensor is not triggering the ECM quickly.... on 98-99 wranglers, this was a problem area. Check terminal connectors at the ECM, clean and secure, another area of concern.The module on the side of the throttle body is the air idle control 'motor' as jeep calls it. Over time they tend to carbon up and it results in bad air/fuel mixture and yet fails to send a fault code, you can remove & clean also the O2 sensor in front of the cat. convertor.remove & clean. Check fuel pressure, you should have some residual PSI. Treat fuel system with a good treatment...I like the Lucas products, their fuel system treatment and injector cleaner burns hot & clean.
I hope these suggestions help...and the wrangler returns to top form...good luck.

can't really go wrong with synthetic oil as long as the grade and weight of the oil is equivelent to what is in there now.

you could have vacumm problems making it seem like the timing is off, but the other guys are right on the timing!!!! it could be throw-body problems, like crack manifold problems. This year has thhis type of problem sometime. Try spraying WD-40 around the vacuum hoses, & manifold to see if the motor changes rpm????