Hi everyone. Again.
so my 99 cherokee has slowly been getting worse over time. It is now to the point where at idle no matter the temperature of the engine or outside, it sounds like a big cam, supercharged v8. Revving up, stalling, repeat. I've replaced the throttle position sensor, camshaft position sensor, and crankshaft position sensor with parts I got at advance and autozone. It has new spark plugs that are gapped correctly, a new distributor Cap and rotor. I think either the sensors aren't any good or maybe my injectors are dirty/bad? I've really stretched my knowledge thin here and any help would be appreciated. Keep in mind it's my secondary vehicle and it doesn't move a whole lot.

 

With all of these symptoms, I'm assuming the check engine light is on? If yes, have you pulled codes and it codes were present, post them here...the exact code, not just a description. Even if CEL is not on, check for codes anyways, might have a pending code or two.

 

Check the Idle Air Control valve. It's on the throttle body and gets gummed up, especially on vehicles that don't move much. Clean it thoroughly with throttle body cleaner.
After that, the most common culprit with those symptoms and your parts list is a bad MAP sensor. Test it or try a known-good one. Those cheap store sensors also fail new-in-box often.

 

The check engine light is on. But for some reason I can't get an obd2 to connect to the ecu. I know there were codes on it before all this happened that hadn't been cleared from previous repairs. I'll check it out and see what I can find. Thanks.

 

Get a shop manual - testing procedures and a list of codes are contained in a manual. A simple VOM can test the sensors BEFORE you buy them.
This is my drill, because I'm bad at guessing - get a shop manual, a VOM and a cold one. If you don't have auto mechanic leads, you can use alligator clip leads to grasp push pins that penetrate the wires. Assuming your air filter is clean, spark plugs, cap & rotor and wires are good, check for dangling wires grounding. The wires coming up from the O2 to the fuel rail wiring harness are a good place to start. Craw under it and survey the wiring and the evap line. Then open your shop manual and test your sensors: the temp sensor, idle solenoid, MAP, CPS and TPS. In my experience, the crank position sensor is good - or you stranded by the side of the road - but test it anyway. If they are good and your throttle body is clean, move to the injectors: clean them and test the resistance for each one. You can pull them and use a 9v battery to produce a click unless it's defective.