Lifters nocking on my jeep cherokee

which engine? "size"?
ever seen a $5 stethoscope.?
using it, you can find any source of any noise. easy.
ever do an oil change every 5k? on older cars , ?
using 10w-30 or 10w-40 oil? not 5w?

Lifters generally make a tick, tick, tick noise. If you have a low tone knock, you may have more severe issues, or what you may have is heavy carbon build-up on the pistons, contacting the cylinder head(s). What I suggest first is to use fuel injection cleaner and add it to the fuel tank a few times. You can go to your local part store and see what other products they have, such as "Seafoam," to assist in carbon removal. Extreme conditions may actually require the removal of the cylinder head(s) to gain access to the top of the pistons to physically scrape the carbon from them.

clicking sounds that increase with motor speed can be a number of things, it can be a bad belt, water pump, or anything else run by a pulley , a stuck lifter, or even a bad cylinder. I'd need a little more info to help you,, Does it just tick, or is it a low thumping sound? slight ticking sounds can be a arching spark plug wire going to ground, those are easiest to locate when its dark and just looking at the motor while its running, you see the spark. If you could narrow the sound down a little, I could be of more help

Sounds light you need to change the neutral safety switch. You should be able to start it in drive. This could account for the limp mode..

What kind of sound? If it's a ticking sound from inside the valve cover it could be a bad rocker arm, worn lifter or lifter & cam lobe or broken valve spring (needs to be looked at). If the noise is deep and best heard at the oil pan. it could be a rod bearing or main beginning to go but generally, that lowers oil pressure. Another item that sounds nearly the same is a cracked flywheel. Careful listening can often unravel this or have a very experienced tech look at it....(still your choice on who does the repair).

U need to have a mechanical tester hooked up anf the oil pressure measured, sounds like u may have a defective oil pump and the low oil pressure is allowing the hydraulic valve lifter to collapse, don't continue to drive this, u will burn out the engine bearings.

could be the switch one side not working test with meter

Ticking can come from so many places I could write all day... Use a screwdriver or a long extension as a stethoscope and try to isolate the source. Best guess I can make without seeing/hearing it is either you cracked an exhaust manifold or a valve lifter is sticking (only a guess) If it's a lifter, you can add a quart of marvel oil and usually it will quiet down.

I would not believe any thing some parts store loser told you. Theres not a V8 built that doesnt have hydraulic lifters, unless its some fancy racin engine. It has hydraulic lifters, but unless you dont change your oil every 5k miles and/or use some cheap oil, there should be no problems. You should have a real mechanic look at it, and verify that you have good oil pressure. If it does, I would change the oil and use some MOBIL 1 and drive it, the oil will clean the lifters somewhat. If the eng has low oil pressure, that will need to be addressed.

I have the same problem on a 2.7 diesel and the problem is that 1 of the washers on the injectors needs replaced.