Easiest way to diagnose misfires?

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ejay

ejay

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Searched nearly the whole mess of wiring and can't find any pinch points, burns, scuffs, areas too close to something hot. Pulled the injector clip on cylinder one (yeah that gave me a new code) and listened with it connected and not connected via sound probe and can hear the difference in actuation vs no actuation. Coils tested OK last week. CPS tested OK via OHM meter. Injectors also tested OK via OHM meter. New iridium plugs installed last week and properly gaped. Idled rough today but went away on test run and smoothed out. Threw an O2 bank 1 sensor 1 code. Drove 100 miles. Idle OK. Paid DMV and returned home. Two miles from home P301 pops up and rough idle again. I don't get it. Any ideas on what to test next?

May have to bite the bullet and send it to the local mechanic for diagnostic. I hate doing that unless I have to.
 
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I would pull the injectors but reality is that I wouldn't know if they were dirty enough to be clogged just by looking at them. Any idea what four port injector would be a good upgrade? I've read Dodge Neon but don't have part numbers. Or should I not bother with an upgrade (or four port hype) and source a set of new ones? Good brands?
 
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ejay

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Well, I purchased a set of Bosch re-manufactured four port injectors off ebay last night. They should arrive by Friday. I'm going to see if that's my issue.
 
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ejay

ejay

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I battled an intermittent misfire problem on my 97 with 151k miles for 2 years replacing everything dist cap, wires, etc.
Finally checked timing chain slack at 175k which showed 8 degrees slack.
Replaced timing gears and chain and all misfires gone, period.

View attachment 133860
I've got all the tools I need to do the timing chain as I've done it before in my old XJ ten+ years ago. Like hell I want to do it. Jez, I hope it's not the timing chain. I can't even test this theory without removing the front end to take a look.

 
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KCsTJ

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I've got all the tools I need to do the timing chain as I've done it before in my old XJ ten+ years ago. Like hell I want to do it. Jez, I hope it's not the timing chain. I can't even test this theory without removing the front end to take a look.

It is a bit of work but if that timing chain has too much slack it's gotta be replaced. Yes they are sposed to last the life of the motor but they do stretch from wear. To me that chain has too much slack. I would replace it. Nice video.
 
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It is a bit of work but if that timing chain has too much slack it's gotta be replaced. Yes they are sposed to last the life of the motor but they do stretch from wear. To me that chain has too much slack. I would replace it. Nice video.
Lol I did. Over ten years ago. On the XJ. I've never opened up the TJ.
 
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ejay

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The struggle continues.

Replaced the injectors. Started it up and rough idle. New codes, P0031, P0051, and P0132.

Drove it a few miles and the idle smoothed out. Smooth as a baby's butt. Was happy.

I pulled over to pull the battery cable as clearing the codes via scanner wasn't clearing the CEL.

Still idling fine. Codes came back and then the 'check gauges' light. New code P1682.

I noticed a slight leak on one of my injectors. Going to reseat it and drive it a while. I hope that the new codes are the computer trying to relearn. Didn't have time to go further today due to rain.
 
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I tightened up a pos cable that was loose. Reseated the leaking injector. Started it up. Idles smooth as ice. Better than it ever has before. +1 for the four port injectors; at least in that regard.

All codes cleared except P0031 and P0051. Those remain and return after cleared via Blue Driver. I'll drive it on Saturday and maybe it will clear on it's own after some computer learning.

20200116_170558.jpg
 
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ejay

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Sounds like progress (I hope!).

You didn't say what brand O2 sensors you're running, but our TJs are known to be very picky about it. Check out this thread for the reason why and links to the ones you should be running..
So I've heard. I can't recall what brand I have. Could also be the fuel/air ratio is off (not yet learned) and the O2 sensors are in code because they don't know what temp to be based on those mixtures. If that's the case (and if I'm not talking out my backside with that logic) it should re-learn on their own.
 
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