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Old 08-30-2019, 09:49 PM
Thread Starter
Join Date: Aug 2019
Posts: 8
97 2.5L troubles

Hi all,

I've been having an issue with my Jeep for quite a while and I haven't been able to solve it. I'm trying not to go down the route of throwing parts at it. The jeep struggles, or hesitates, upon acceleration (for example after a red light), bucks for a bit, then seems to normalize and drives fine. This happens intermittently. Also, at idle sometimes I notice the tachometer fluctuates and I can hear the engine sounding rough. Another thing it does, after refueling gas all the way full, immediately after start it idles rough and bucks on acceleration, then it normalizes. You might be think it's fuel pump related but I've replaced it with a new fuel pump, (after the other failed in just 5 months). I've replaced the upstream o2 sensor as well with NGK. I don't get any check engine lights while these symptoms occur. I have however received an engine code for misfire on cylinder 2, and just cylinder 2 but that happens seemingly randomly, and it usually goes away on its own.

One of my friends thinks it could be a bad ignition coil. I'm not sure.

Any suggestions on where to start is appreciated.


1997 2.5L Auto

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Old 08-31-2019, 06:47 PM   #2
Join Date: Apr 2013
Posts: 12,706
Failing Coils can be heat related

If the miss is rpm specific it may be an easy fix

Otherwise inspect battery cables both ends and tub ground

Also observe under hood at night in dark with engine running for any spark arching (but keep hands far from belts fans and pulleys when observing in dark)

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Old 09-01-2019, 10:31 AM
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Join Date: Aug 2019
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Thanks. You make a very good point. I notice the misfires at idle RPM range, under 1000. It happens intermittently but it seems to happen after running it for awhile once everything gets hot, I don't notice it much from a cold start.
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Old 09-06-2019, 09:09 AM   #4
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Join Date: Feb 2018
Posts: 84
When is the last time a general tune up was done?
Spark plugs, wires, distributor cap and rotor.

What color are the spark plug ceramic tips?
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Old 09-10-2019, 01:35 PM
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Join Date: Aug 2019
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You were right! I did a basic tune up, distributor cap, rotor, wires and plugs and the problem went away completely. Ultimately it was probably the spark plugs being kinda old, but I went ahead and replaced the other parts considering they were already old and worn. I'm glad it was an easy fix. Thanks all for the suggestions!
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