Losing power and jerking while accelerating

2001Wrangler

2001Wrangler

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Cumberland, Maryland
I have a 2001 Jeep wrangler with a motor out of a 1995 in it. its a 4 cylinder and has about 190,000 miles. After it heats up only, the jeep will start to cut out of power on and off. it doesn't last long but it makes the car jump especially at higher speeds or in a higher gear. it feels as if I were to take my foot off the pedal for asplit second and slam it back on. any ideas of what this could be? thanks!
 
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I believe this would more so belong in the general discussion topic than the How to Guides. I would move it there to get your answers.
 
@2001Wrangler - Glad to see this post. My jeep is doing this exact same thing. 97 2.5L with 174k. The whole jeep bucks when this occurs.
Have you had any luck diagnosing?

Bizarre, doesn't happen unless I drive more than 50 miles or so.

I'm not sure where to begin looking
 
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@2001Wrangler I'm happy to help diagnose if you havent found the cause.
Monday I'm talking to a mechanic face to face about possible causes. I'm determined to find the problem.
The jeep runs like a new engine except for this crazy engine hesitation. And no engine codes which doesn't help.
I think we have the exact same issue, very glad to see this post.
 
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KCsTJ said:
@2001Wrangler - Glad to see this post. My jeep is doing this exact same thing. 97 2.5L with 174k. The whole jeep bucks when this occurs.
Have you had any luck diagnosing?

Bizarre, doesn't happen unless I drive more than 50 miles or so.

I'm not sure where to begin looking
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Was my TPS sensor, but threw a code. Only use Mopar sensors or it won't fix it and u LL be still chasing the problem. Mine was after 15 miles and same symptoms. Should have a code tho
 
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That it only happens after it has started to warm up points to the upstream O2 sensor. If you replace it make sure you ONLY install an NTK brand, avoid Bosch which doesn't work well in our jeeps.

O2 sensors are like spark plugs, they eventually go bad and have to be replaced. I wouldn't bother replacing the downstream O2 sensor which only monitors the catalytic converter.
 
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KCsTJ said:
None whatsoever. And I check both ways, via the ignition key x3, and with an obdii reader. Nothing.
Click to expand...

Whenever I hear low power, the first thing I think of is clogged cats. Not saying that's the issue, but when mine had clogged cats it was low on power and jerky. Of course I also had codes to go along with it, but that's not always the case.
 
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Jerry Bransford said:
That it only happens after it has started to warm up points to the upstream O2 sensor. If you replace it make sure you ONLY install an NTK brand, avoid Bosch which doesn't work well in our jeeps.

O2 sensors are like spark plugs, they eventually go bad and have to be replaced. I wouldn't bother replacing the downstream O2 sensor which only monitors the catalytic converter.
Click to expand...
Yep thanks Jerry. The upstream 02 sensor is Bosch, the right one, with about 20k miles on it. But I have a brand new spare I can try in order to troubleshoot.

Bizarre thing is that it doesn't happen till a good 50 miles or so driving.

Edit: I typed Bosh up there ^^ meaning to type NTK, , MY mistake
 
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Chris said:
Whenever I hear low power, the first thing I think of is clogged cats. Not saying that's the issue, but when mine had clogged cats it was low on power and jerky. Of course I also had codes to go along with it, but that's not always the case.
Click to expand...
I should add I replaced the main cat last month so that is new. My 97 has no precats.
 
Leinhit said:
Was my TPS sensor, but threw a code. Only use Mopar sensors or it won't fix it and u LL be still chasing the problem. Mine was after 15 miles and same symptoms. Should have a code tho
Click to expand...
@Leinhit I'm going to try that. I replaced the TPS sensor when i bought the jeep at 151k but being a new jeeper did not make sure it was Mopar.

It is like the fuel shuts off for a split second, looses some power then I have to nurse it home at high rpm so it won't buck.

I'll get a new Mopar TPS sensor and try that. And will report back the results of that effort.

Thanks for your response.
 
KCsTJ said:
@Leinhit I'm going to try that. I replaced the TPS sensor when i bought the jeep at 151k but being a new jeeper did not make sure it was Mopar.

It is like the fuel shuts off for a split second, looses some power then I have to nurse it home at high rpm so it won't buck.

I'll get a new Mopar TPS sensor and try that. And will report back the results of that effort.

Thanks for your response.
Click to expand...
I have a thread on my experience here. But I did have a code to start with. I chased the problem cutting and soldering in New grounds, took the steering wheel off and clock spring test,etc

I purchased a new TPS and had the same continuing problem. I did all kind of things for the next month until I broke s down and purchased a Mopar sensor as advised on this forum.

Instant fix and never been better.
Buy on Amazon and return it if it doesn't help.
 
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@Leinhit Could the clock spring be a possibility? The P.O. bypassed the horn and I plan to repair that. Could this somehow contribute do you think? I have never checked the clock spring.
My gut says its fuel related somehow. Hope so thats easier to diagnose n chase down.
I will follow up with any results.

20190802_140200.jpg
 
KCsTJ said:
Yep thanks Jerry. The upstream 02 sensor is Bosch, the right one, with about 20k miles on it. But I have a brand new spare I can try in order to troubleshoot.

Bizarre thing is that it doesn't happen till a good 50 miles or so driving.
Click to expand...
Don't bother installing that spare if it's another Bosch. Bosch O2 sensors require a different bias voltage to work properly than our Wranglers provide.
 
KCsTJ said:
@Leinhit Could the clock spring be a possibility? The P.O. bypassed the horn and I plan to repair that. Could this somehow contribute do you think? I have never checked the clock spring.
My gut says its fuel related somehow. Hope so thats easier to diagnose n chase down.
I will follow up with any results.

View attachment 107757
Click to expand...
There are threads about clock spring problem confusing the computer into thinking it is aTPS problem. But I think it always has a code with it. The clock spring is like a long extension cord.. I tested mine by seeing if it had continuity from one end to the others. Not 100 percent test but good to start. Short answer.. I don't know. Did the PO bypass the clock spring for the horn?
 
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Leinhit said:
There are threads about clock spring problem confusing the computer into thinking it is aTPS problem. But I think it always has a code with it. The clock spring is like a long extension cord.. I tested mine by seeing if it had continuity from one end to the others. Not 100 percent test but good to start. Short answer.. I don't know. Did the PO bypass the clock spring for the horn?
Click to expand...
I'm not sure, the P.O. installed an aftermarket horn button to pass emissions.
So he may or may not have messed with it.
I am changing out the TPS today and see what happens there.
Thanks for your feedback.
 
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