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chief100psu 12-16-2008 05:21 PM

Loss of power up hill
Coming home from work - going up a large hill - it started to bog down around 3500rpm. Clutch? Engine seems fine. No check engine lights - not sure where to start.

Jerry Bransford 12-16-2008 06:26 PM

Details man, we need details. Jeep model year, engine type, transmission type, tire size, and axle ratio size. And when is the last time you did a tuneup?

chief100psu 12-16-2008 06:56 PM

Details - sorry :)

1998 - TJ - 2.5 - stock - manual - I think 4:10's whatever came stock

2 months ago - plugs/cap/rotor

Just noticed it today on the way home. It wasn't gradual - all of a sudden.

Jerry Bransford 12-16-2008 07:25 PM

Is there a check engine light? Since you can't generate your own diagnostic codes on a '98 like you can on most other model years, I'd take it to an auto parts store like Autozone to have them read any stored diagnostic codes. Since you did a tuneup only a few months ago, it's possible the upstream 02 sensor has gone bad which is making the air fuel mixture too rich. If the parts store can pull any diagnostic codes for you, it will at least head you in the right direction.

chief100psu 12-16-2008 07:50 PM

no check engine light - whats a clutch feel like when it is failing

Jerry Bransford 12-16-2008 08:32 PM

Engine rpms climb up unexpectedly, especially when you're in the higher gears. Eventually there will be no mistaking a bad clutch when it starts slipping in 1st and 2nd gears too.

If it is bad, I'd go two Dial-A-Clutch - Your LuK Clutch Kit Specialist and get a replacement clutch kit made by Luk, avoiding the "Gold" version which is noisy when installed in a Wrangler. The entire kit consists of the clutch disk, pressure plate, throwout bearing, pilot bearing, and centering (pilot) shaft and sells for only $140 or so. I specifically would not go with a CenterForce clutch which is not designed for the types of uses typical to a Jeep. :)

jdhallissey 12-16-2008 08:38 PM

engine swap would solve that! haha- I have the same problem i have to downshift one to two gears to make it up some hills with keeping speed.

Triple88a 12-16-2008 09:24 PM


Originally Posted by chief100psu (Post 293642)
whats a clutch feel like when it is failing

you step on the gas, the rpms go up, the speed stays the same. It feels like the clutch is not fully engaged and its slipping. :wavey:

chief100psu 12-17-2008 07:58 AM

Guess it is not the clutch then, doesn't slip just boggs down. I have a cat converter that is rattling (not sure inside or outside) I wonder if it affected the second O2 sensor? No CEL. Still don't know where to start - vacuum perhaps?

Jerry Bransford 12-17-2008 11:40 AM

A bad cat (yours is rattling so it is bad) can reduce engine performance if it becomes plugged. And bad cats often do become plugged, I'd take it to a muffler shop (avoid the chain muffler shops like Midas that tend to rip people off) and have them do a pressure test to see if the cat is plugged and reducing your engine's power.

Jma20a 12-17-2008 11:45 AM

i've had the same issue with my 4 cylinder for a good deal of time. i replaced the o2 sensor and that seemed to do nothing, next i guess i will have my mechanic test the cat.

Jonny15 12-17-2008 02:32 PM

So it just all of a sudden started doing this? I was gonna say i have a 2.5 manual and at times i need to go to second to make the damn thing go up really steep hills and even then it sounds like its breaking a pretty big sweat. Guess that's the fun of owning a 2.5 lol

Jma20a 12-17-2008 03:40 PM

my loss was slow to grow to where it is now, was thinking that a 4.0L throttle body would help.

chief100psu 12-17-2008 05:18 PM

Sweet - searching through the post I found a link to the Jeep site that shows recalls - my jeep is eligible for a replacement cat!! I was rattling anyways - hope this is also why it is bogging down - This forum is great! I will let you know if it was the cause.

Jerry Bransford 12-17-2008 05:26 PM


Originally Posted by Jma20a (Post 294038)
my loss was slow to grow to where it is now, was thinking that a 4.0L throttle body would help.

Jp magazine tested that combination and found it actually caused a minor loss of power.

Triple88a 12-17-2008 06:10 PM

i would be interested to see the dyno behind that statement.

Jma20a 12-17-2008 07:06 PM

x2, ive been told it helps with power loss and possible slight better of gas millage

Jerry Bransford 12-17-2008 08:22 PM

I'd take it up with Jp magazine editor John Cappa then, he's the one who tested the combination and wrote about the results.

chief100psu 12-18-2008 04:04 PM

final update
Just an update in case this is ever found in a search. The catalytic converter was the issue and covered by a recall from the stealership. They did make me pay for the second O2 sensor.

Check for recalls here Jeep recalls

Thanks for the help all!

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