Please help .... I own a 1988 Jeep Cherokee Limited Edition 4.0L

For a couple weeks now, my jeep seems to spudder when I would go on the freeway (over 55 mph) but seemed fine on the main roads. Then a couple of days ago, it began knocking and lacking power. We removed the air filter which was saturated with engine oil. Apparently the valve cover gasket was leaking and the oil had run out so we filled the oil which helped some until we could fix the valve cover gasket later that night. It still didn't want to go over 35 miles per hour without reving it up real high. So when we got home and took off the valve cover we were amazed to see the sludge inside the on the rocker arms and on the cover itself. It was so thick it was almost like hard plastic. We were taking it off in chunks. We scraped it clean and cleaned as much of it off as we could. Then we replaced the gasket and performed 2 engine flushes to clean it the rest of the way. The CCV valve and tube were so clogged we needed to spray it down with brake cleaner to allow vacuum to go through. When we would rev the engine up, oil would shoot out the PVC hole where the vacuum hose harness assembly was attached. We went to the junk yard and bought another vacuum hose harness assembly which was too filled with sludge to clean and the tube was broke. And we replaced that one. We replaced the spark plugs and since the wires broke when removing them from the plugs, we were forced to replace them as well. We gave it a new oil filter and a new air filter ....

And the problem seems to still be there.... It spudders and loses power and can't seem to get over 25mph without reving it up extremely high.... like it's stuck in 2nd gear. I need help! I'm lost. I don't know what more to try. Could this be a vacuum issue? And O2 Sensor? Fuel Filter? Too Many Questions? I'd appreciate any input you could give me.... I use this vehicle for work and can't afford to keep replacing things blindly.

If you haven't replaced the fuel filter do it now. Is this vehicle an automatic?

I thought I'd try that one but it seems like it may be somewhere in one of the vacuum lines somewhere. After reving the engine up to 3500 rpm it will eventually drop into 3rd gear and then I can go to 45 miles per hour. But if I happen to stop the process starts all over again...

Yes it's an automatic.

I've spent so many hours on this thing that I think I'm going to take it into AutoLab and have them test and hopefully tell me what the problem is. I'll keep everyone updated. They open tomorrow .... I hope it's something small .... Can't afford too much....

I thought I'd try that one but it seems like it may be somewhere in one of the vacuum lines somewhere. After reving the engine up to 3500 rpm it will eventually drop into 3rd gear and then I can go to 45 miles per hour. But if I happen to stop the process starts all over again...

Yes it's an automatic.

I've spent so many hours on this thing that I think I'm going to take it into AutoLab and have them test and hopefully tell me what the problem is. I'll keep everyone updated. They open tomorrow .... I hope it's something small .... Can't afford too much....

the fuel filter is mounted on drivers side frame right behind rear wheel. check the condition of the fluid in trans, and have filter changed. Dale jeepman600@sbcglobal.net :disappoin

:disappoin

Sadly, I took it to Total Automotive Care and they said it was my transmission. It still drives but we need to get it revved up to 4000 rpm in order for it to settle into 2nd gear. (I was wrong earlier when I said it would drop into 3rd .... only 2nd - and that's where it stays until I have to stop and start it all again)....

I was so hopeful that they would tell me something like I've been hearing on here....TPS (Throttle Positioning Sensor) .... Fuel Filter or Vacuum Lines.... but they said transmission. I can't afford that so I guess I'm on the hunt to find another vehicle .... :disappoin

Thanks for the input though .... :smile: