I have a 96 ZJ 5.2 L with a severe missfire problem. The problem started about 2 months ago. It started off not so bad and would only missfire everyonce and a while. Now it missfires at idle and starts severly missfireing (as in it shakes the truck so bad it knocks the off road lights out of alignment) at exactly 45 mph. I've noticed that it will run better on very cold days (20 degree's F and below) and run worse on warmer days. The following are the things I have already done to try to fix the problem....

Changed the fuel filter
Changed the Cap, Rotar, regaped all the plugs and inspected the wires
Replaced the ignition coil


The check engine light is on and I have taken it to two different shops to have the codes read and they both got "random or continuous missfire on all cylenders" or code 43 if you cycle the key yourself on-off-on-off-on.

Not sure what to do at this point. I'm starting to think it may be a sensor issue but not sure what sensor or sensor's it could be. Or possibly a fuel injector problem. Does anyone have any ideas? Please help if you do :)

engine compression?

Have you done a vacuum test ?
Checked if the injectors are getting voltage using a noid light ?
Compression test of the cyclinders ?
Test to make sure you are getting battery voltage at the coil ?
Listen to each injector using a stethiscope or equivalant to make sure they are functioning ?
Check to see if the catalytic converter is plugging up ?

Just a few thoughts

You might want to have a look here....same engine:

Thread. (http://www.automotiveforums.com/vbulletin/showthread.php?t=407879)