1990 4WD Mighty Max!

[SubGothius]

Your replies got stuck in the Moderation queue, not sure why. I went ahead and approved them all, since any one of them may have some useful clue(s) that didn't appear in the others.

If the plug had good spark when removed from the cylinder is dist cap even worth replacing?

Not quite clear what you mean by "plug had good spark when removed from the cylinder" but your process of elimination does sound like the terminal in the cap for that cylinder might have a crack or other fault.

Could also be a bad fuel injector on that cylinder. Try swapping injectors around and see if the problem follows the suspected-bad injector. If not, could be the wiring to the #3 injector.

Another thing to check would be compression; if #3 is a lot lower than the others, that could be the issue.

[OR3X]

Your replies got stuck in the Moderation queue, not sure why. I went ahead and approved them all, since any one of them may have some useful clue(s) that didn't appear in the others.



Not quite clear what you mean by "plug had good spark when removed from the cylinder" but your process of elimination does sound like the terminal in the cap for that cylinder might have a crack or other fault.

Could also be a bad fuel injector on that cylinder. Try swapping injectors around and see if the problem follows the suspected-bad injector. If not, could be the wiring to the #3 injector.

Another thing to check would be compression; if #3 is a lot lower than the others, that could be the issue.

Thanks Sub! I thought I was losing my mind! I did a compression test yesterday and the misfiring cylinder only has ~30psi of compression. I don't have any more time to mess with it this week, but I'm going to get the valve cover off next week and see if there's any obvious issues with the valves on that cylinder.