Hate to dredge up an old thread - but I've been doing quite a bit of research on how to fix the stupid "43 Peak primary circuit current not achieved with maximum dwell time. Misfire detected in one or more cylinders 1 thru 6. (4 and 6 cyls.)" error code apparently so common for these TJ's. I've replaced the cap, rotor, plug wires and plugs, tested the plug wires and pretty much everything else I can do or have read to do. The only other thing I can think of is replacing the valve springs. Considering my engine has over 225k it couldn't hurt anyway.
All the posts I read give various ways to keep the valves from dropping - compressed air, TDC, screwdriver, cotton rope, etc. My question is - why not just take the head off and do it that way? If my valves are as gunked up as I imagine they are, that would make it easier to swap the springs and clean the valves right? Granted, I haven't torn into this type of engine before, but I did take apart a 1965 Mustang engine once - taking the heads off wasn't that much harder than taking the rocker cover off. I'm betting there is some reason why I shouldn't though - right?