Please help with diagnosis...

hi kelly, my money says your catalytic converter is clogged.

also..........might could be fuel pump........

There are many responses from CAT to fuel pump. You have a 1998 and I can't see the CAT being bad and if it was the fuel pump, you wouldn't be able to drive around town or anywhere.

I think you have blow-by into your intake. Have you checked your air filter lately? You will probably need to clean or replace your CCV and the hoses. The intake hose to the valve cover too. You should also inspect your ribbed intake hose going from your air filter cover to your throttle body for cracks or looseness. Also check your MAP sensor module with a vacuum pump to see if it's holding vacuum.

You did okay with the electrical, now try the intake side.

I'd guess clogged cat, clogged fuel filter, or fuel pump getting ready to go on vacation. Dunno if a jeep will do this, but on a Mazda, attempting to limp too far with a clogged fuel filter resulted in cooking the front catalyst to an early death.

hi bill, im curious about your recommendation. every CPS problem ive ever found, the CPS was either good or bad......ive never seen it run fine at 1 rpm and poorly at another.

LOL....Thanks folks! Allot of possibilities indeed!!! I do appreciate the input. I'll let you know what I find out...Wish me luck.

Regards, Kelly

LOL...Thanks>

Sounds like what happened to me on a Dodge Ram. That turned out to be a CPS. That took a while to figure that one out. I just put in an upstream oxy sensor in my 97 TJ having similar problems to what you described and what a DIFFERENCE!!! Of course I was getting the computer codes with the key telling me what it was. What do your codes tell you if any? Good luck,

Kevin

Had a CPS problem, ran fine most of the time...then on occasion it would hesitate, back fire, dog down, etc. Granted this was mostly when I put my foot in it, but not always.