so ive been told, and im finding out, that all 4.0's get a tick within their lifetime. mine seems to go between cylinders 5 and 6. i ran some lucas. still ticking. i was told to run injector cleaner and a higher grade fuel, possibly to help with carbon deposits. any other ideas?

 

Other than tearing it down?? Fresh oil + filter. They do all seem to make noise. You could try kind of an old school engine flush, drain a few quarts of oil and refill with dexIII atf. Idle the engine for 15-20 min then drain, change oil and filter. The deturgents in the atf will clean the internals of the engine and maybe help the lifter tick.
Good luck!

 

I have the same thing, although it seems to go away once the jeep is running for a while which makes me think it is a lifter. I may take off the valve cover and check all the rockers. I don't have much experience on these... mostly on older v8s, but that's what it sounds like to me... either a compressed lifter or some play (i.e. loose rocker, rod issue) I put some marvel mystery oil in the other day but seems to be the same.

On my 350 I can just run the motor with the valve cover off and make my adjustments... a little messy but works. When I did my 5.0 I just rotated the crank and worked on the valves that were closed then rotated and repeated. I'll have to check the book and do some research on the best way to check on these. Are they pedestal mount? torque spec? Anyone have any experience with these?

Keep us posted, good luck. It seems like these motors can handle running like this for a while.... I dunno but I'd like to find a solution. I also have rough idle and am about halfway through all the typical maintenance stuff.