Well, This is what I do when I have a jeep with a lifter tick. Do a hott oil change, fill with new oil leave old filter. Run for a few mins at various rpms, then change oil and filter. After that run the engine until it's warm, Then run it at a high idle. I start at 3k rpm. Leave it there for 30 seconds, then go to 4-4.5k and leave it there for 5 minutes. 3 at a minimum. Only bring it down if your engine temps start going up or something horrific sounding is happening. In that case you also have other issues. After you've held it at a high idle of at least 4k for at least 3 minutes bring it down in steps. Then finally let it idle for a few minutes and shut it off. After check your oil, if its dirty change it again. Then repeat the high idle. After this watch your oil color when its getting close to the next oil change run a can of seafoam in the engine for a few hundred miles. I've done this to many of Jeeps with good results every time. I have a 91 with 250k. I bought it off a friend. It had a stuck lifter for 2 years or more, I had it for an hr and the lifter was unstuck. I changed the oil a few times then the filter and am running 15w-40 Mobil Delvac. One time after it sat for a month it had a slight lifter tick for a few seconds. I ran it at a high idle for a few minutes and it never came back. Jeep went from getting 15 mpgs to 21 mpgs last road trip I took it on. Only thing I did was fix the lifter tick and put new tires of the same size on it.
