hello everyone!
i am new to the forum, but have consistently read threads while troubleshooting my jeep. i figured i would start a new thread since i haven't found one that is quite like my issue.

i have a 1994 jeep cherokee se 4.0L I6 4x4 with a 5 speed manual transmission. it is at 156,000 miles and in the last three months i have had an epidemic of problems!
i will start off with the first ones (which i have since fixed):

november:
rough idling and bucking.
replaced the fuel filter, patched a vacuum leak, new air filter, and cleaned the throttlebody/iac valve.
started throwing lean/rich mixture codes. replaced O2 sensor. all good. changed the oil.
everything seemed fine afterwards, and then on a trip to portland, or my catalytic converter started to rattle pretty good.
by the time i made it home to slc, ut the rattling was gone and the jeep ran well.

december:
on christmas day i pulled onto the interstate, and noticed a HUGE lack of power and acceleration. couldn't get above 45 mph, and at around 1700 rpm i noticed a loud yet low hum from the front of the jeep, and noticed my temperature gauge rising to about 3/4. i could get to about 2500 rpm with essentially no response, just the humming.

january:
changed the oil at 3,000 miles from the previous one, dosed the gas with seafoam and in a day or two it started to run great!! less than four days after that it resorted to it's old ways and ran worse than it had before! it seems like it isn't getting gas, but it's certainly burning it (also no lean condition codes. no codes at all).
changed the fuel filter. replaced the tps sensor.
nothing.
now it has a hard time starting, and will stall at idle. undrivaeble!
i think it may be my catalytic converter, but the u bracket is pretty much welded on. thinking about sawing it off but figured i'd get some advice from you folks before hackin' things apart or before i admit defeat and take it into a shop!
i was just underneath it before i started writing this, and noticed a lot of oily spray on the undercarriage where the transmission meets the rear drive shaft. . .

i appreciate your time, and suggestions!!! i am really bummed i cannot drive my jeep!!!

 

When was the last tune up ?

 

over the past three months i have pretty much changed everything. i also replaced my sparkplugs about three weeks ago, and bought new tires in november. the only thing i haven't replaced is the distributor cap/rotor. the timing seems right though, and the plugs all had nice color.
am i missing something?

 

You may have a clogged cat. You can use a simple vacuum gauge to test your catalytic converter. Here is a link to a good article on the cat and troubleshooting it.

http://www.aa1car.com/library/converter.htm

And I would also recommend that you finish your tuneup. Distributor cap and rotor are inexpensive. Get the kind with "brass" contacts, rather than aluminum.

 

^^Great advise as usual. Vac gauges are inexpensive. I had a "K" car once. (OK, a GF had a K car!), had no power. Really had me stumped. Finally I loosened the nuts holding the header pipe to the manifold. BINGO! Night and day. Fairly easy only if your nuts aren't seized. That said I don't want to be responsible for you needlessly breaking a stud on your manifold. If you go there and they come easy, it can be an easy way to find if that's your issue.

I haven't tried pulling the 02 Sensor.

(saving that link TJ, thanks!)

 

I hate it when that happens......

 

 

right on. thanks tjwalker!
i am pretty sure it is my cat, but checking the pressure will be better than hacking off the cat bracket.
and i will replace the distributor cap/rotor a.s.a.p.

thanks again.