I did a fluid and filter swap about 8k miles ago but I haven't even thought of checking the fluid level. If that is low it could explain the uphill problems for sure so I will have to check that ASAP.

 

I have a 98 XJ with a manual transmission, and have a similar problem. Engine runs fine around town at lower speeds, but under load (going up hill and Highway in 4th and 5th gear) the engine is rough and powerless. Once I get above 65 it smooths out. I've replaced the plugs, cap, rotor, spark plug wires, oil, and I even took the drive shaft clearance dent out of the exhaust pipe (wasn't easy). It just paseed emissions testing, so I don't think I have a plugged Cat. No check engine light either.

 

I read that the coolant temp sensor and the 02 sensor have a lot to do with open loop/closed loop transition so I bought each of those last night along with a new thermostat. I will replace those tonight and see if that makes a difference. If not I am gonna drill a small hole in the exhaust and use a little scope to see if the cat is blocked.

 

Well, so far this is what I have done to fix the slow uphill issue. Replaced stock injectors with Bosch 4 hole ones, no change. Replaced cat, good change, i now have compression at least more than I did going up hills, also the ac dose not switch to window defrost as fast, so the proper back preasure appears to have helped that issue as well. Unfortunately the stuff was so rusty I ended up replacing all of it. 200.00 from autozone to include the cat, gaskets bolts etc. Gas millage should improve as well, since the engine will not be fighting itself.

Note, the improvment is not dramatic but for a 23 YO jeep with 180k on it im happy.

BTW the exhaust out of the tailpipe is still really hot....Dont know why?? Anyone have the same issue?

 

So I replaced the cat with a straight pipe for testing purposes and absolutely no change. For the record, it didn't look the least bit clogged. I also replaced the O2 sensor and the coolant temp sensor and still no change.

Any more ideas????

 

maybe the other o2 sensor?

 

Adjust the TV Cable, thoroughly clean the throttle body, test the TPS and replace as needed.

 

you should have just took out the o2 sensor in front of the cat instead of taking it out but oh well im a little late

 

There is only 1 O2 sensor on a 94

Ok so I cleaned the TB which wasn't very dirty. Adjusted the Kick Down cable (ony cable on mine that has adjustment) and tested the TPS. 5.0 V input and varies from .88 to 3.9V depending on throttle position so that all seems to be within spec.

This is driving me NUTS!!!

 

Have you done a compression check?

 

Flexplate! My 91' was the same way.

 

You ever figure this one out 😅