Continued Engine Issues. Help!

[QuinnD]

Hello, I posted here about 6 months ago about starting to mod my 2000 Jeep Cherokee XJ for overlanding, however, there have been persistent engine issues. Currently, the most troubling one is a consistent but random misfire on cylinders 1 and 3. Battery connection has been checked and fixed, spark plugs have been replaced, ignition coil replaced, and compression test has been performed, all good there. A potentially unrelated thing: radiator has been flushed, new coolant was added. I've read across the internet that it could be the IAC or O2 sensor which I am unsure of how to check those things. The odd thing is is that it doesn't throw codes very often when the check engine light goes off, even when the check engine light is blinking. Not sure where to go from here, slowly going insane lol.
Edit: These misfiring issues also cause my heat gauge to go out, only happens with these misfires and usually starts working mid-drive.
Edit 2: I do not have a distributer cap I have an electronic ignition

 

[Viking1204]

I assume when you replaced the spark plugs you made sure the gap was appropriate for your particular engine?

 

[socal66]

Could be somewhere in the electronics. I had the exact same issue with a 2000 Dakota truck (which is a totally different engine and platform) and it was a bad throttle position sensor which I replaced and then everything was good after that.

 

[QuinnD]

I assume when you replaced the spark plugs you made sure the gap was appropriate for your particular engine?

I’m pretty sure, it was done by a mechanic a few years ago.

 

[Offroadnutz]

Read about a similar problem on another 2000 on cherokeeforums.com
They ended up replacing the distributer that the cam sensor sits on . Something about the wear in the gear causing excessive movement. ``
If that is the problem, you would need a scan tool synchronize the cam and crank sensors after replacement.

 

[Viking1204]

I’m pretty sure, it was done by a mechanic a few years ago.

On my old 2011 F-150 it would start misfiring every few years and resplacing the spark plugs would fix it.

 

[QuinnD]

I’m pretty sure, it was done by a mechanic a few years ago.

On my old 2011 F-150 it would start misfiring every few years and resplacing the spark plugs would fix it.

Hmm okay I’ll look into that

 

[MidOH]

Cap, rotor, plugs. Remove and clean ground wires.

 

[Alanymarce]

Try replacing the wiring from the distributor cap to the plugs. You may have done this already, and I guess the distributor may have come with new wiring in which case ignore this.

 

[QuinnD]

Try replacing the wiring from the distributor cap to the plugs. You may have done this already, and I guess the distributor may have come with new wiring in which case ignore this.

I haven’t looked into that yet, someone else mentioned checking the cap too, thanks!

 

[Alanymarce]

I haven’t looked into that yet, someone else mentioned checking the cap too, thanks!

I misread the posts and thought that you'd already replaced the cap, so yes - cap AND wiring.

 

[QuinnD]

I haven’t looked into that yet, someone else mentioned checking the cap too, thanks!

I misread the posts and thought that you'd already replaced the cap, so yes - cap AND wiring.

Just discovered I don’t have a distributer cap, I have an electronic ignition (I’m still learning) so I guess it’s definitely electrical

 

[Alanymarce]

Just discovered I don’t have a distributer cap, I have an electronic ignition (I’m still learning) so I guess it’s definitely electrical

hmm - so, check the wiring from the coil to each plug, I suggest.