i have a 96 cherokee sport i bought for parts i drove the jeep home the engine would not rev past 3500 rpm and there was oil in the air cleaner does anybody have any idea what is wrong

 

Oil in the air cleaner sounds like it could a bad PCV hose, the hose that gose from the top of the valve cover to the air box. not reving...stuck throttle leakage maybe

 

The oil is from oil vapor and blowby being sucked into the intake to be burned for emission purposes, kind of a normal thing. Check the fuel pressure and check for a partly clogged exhaust for the lack of RPM.

 

This is most likely your problem. It is a common issue with the XJ. I replaced mine with a slightly larger diameter piece of heater hose and have had zero issues since then.

The hose that comes off the back of the valve cover hooks to a vacum on your intake manifold. It is meant to pull air out of the valve cover. When that hose is clean and getting good suction it will create a vacum that will pull air through the larger hose from your airbox into your valve cover. Because that vacum hose is a smaller diameter hose and is pulling dirty air from the valve cover it often gets clogged. When it is clogged the pressure that builds in your valve cover has nowhere to go but down the larger hose leading to your airbox.

 

thax for the info guys