1997 Grand Cherokee loses power

timing belt may have slipped. usually if the engine starts to back fire and then lose power the timing belt is loose. would check this and replace if it looks suspect. also timing belts should be changed at a certain time or miles witch ever is the grater. average is 4-6 years on a engine that don't do meany miles 2-4 years on a heavy run engine.

change out the throttle position sensor

i think the catalytic converter is clogged up, meineke , midas or somewhere of that sort will test it for free where i live, call ahead and check where you live , it only takes them a short time to do this test, and it sounds like you've spent plenty, its a free test, and can very well cause the problem you say you have GOOD LUCK!!!!!

Sounds like a timing problem, check timing and if off could be timing chain worn out especially if there is excessive miles(200,000 miles or more)

Make sure the ignition coil drive is in proper sync. The sync should be at or close to 0. Also try an engine decarb this works great on 4.0 engines. Also if the misfire is coming for #3 there is a bulliten on installing a heat sheild around the #3 injector because it takeing a lot of heat from the exhaust mainfold that sits right under it.

The likely answer to your problem is that you have an intermittent disconnect in the ignition system. If power supply to the ignition system drops out, some fuel still goes through and when power returns it ignites in the exhaust resulting in a backfire. I would look for a bad ignition switch, or other loose connection that could me making/breaking contact intermittently.

check for leaks in exhaust ahead of converter, check cap and rotor for tracking between contacts, code check for fuel and other faults.

since its a 1997 your jeep has EFI, electronic fuel injection. The most probable reason for your troubles would be the injectors or a problem with the computer controling them, not allowing enough gas to be pushed into the cylinder causing stalling or lack of power, also too much gas iin the cylinder can lead to back firing and stalling. This would also explain the reason it takes so long to start back up some times, all the excess gas in the cylinder is flooding the motor and u have to wait till the gas disipates till the engine will turn over.

its vapor locking try losing the gas cap a little and then drive it around if that works replace it or lust leave it lose

Replaced both CO2 Sensors.