Check any rubber hose pieces between the PVC valve and the motor (intake). Normally a leaking hose will have a soft squishy area in the hose where the rubber is melting and the hose will create a vacuum leak at that point. You can tape over the squishy area with electrical tape (get it tight) and if it runs better you should replace the hose pieces. This leak will cause the motor to run very rough at idle, can cause the motor to race when starting it, can cause the vehicle to shift hard (when motor surges) and can throw scan codes indicating Lean Bank 1 AND Lean Bank 2 (presence of both codes is good indicator that vacuum leak is the cause).
When you removed the plugs, were any fouled or looked different than the others? "Reading" plugs is often a good place to start. You could have a bad injector or a vacuum leak somewhere. I'd also have a code scan done (many larger parts stores do that free). Also a good place to begin testing.
Otherwise, you will need a chilton or haynes manual and a multi-meter. Go through the component tests in the manual and it may give you something to go on. Before testing, check that all fuses are good and that your battery is fully charged. An engine running at higher rpm's will often "pass by" a bad/mis-firing cylinder so quickly that you won't feel a miss as much as at lower rpm's., or sometimes it will clear itself but foul at idle (an injector can do that, as can an obstructed or malfunctioning idle control motor.).
Without testing, I can only make suggestions.You need to do the looking to find the problem.
There are two ways to determine what is wrong. Guessing, where you think about the problem and then rationalize an answer and buy a part
(most likely not the one you need) then repeat that process 'till you have replaced the entire system.
OR, you get a manual and a meter, follow the test procedures and find the problem.
Good that there isn't smoke from the pipe. At least your head gasket is good. But, it wasn't overheating was it.
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CLEAN FUEL INJECTORS BUT IT SOUND LIKE INTAKE MANIFOLD VACUUM LEAK OR LOW CYLINDER COMPRESSION DO A VACUUM TEST AND COMPRESSION TEST.SEE WHAT HAPPENS.
SOURCE: rough idle stalls at low rpm's
check your transmission fluid,the motor will stall when fluid is low
SOURCE: 2003 Jeep Grand Cherokee Runs Rough
I had a simalar issue,replaced lower O2 senser and cured it.
SOURCE: 1998 Jeep Cherokee - hard to start
My 98 Cherokee was the exact same. I used to have to turn the key back and forth 3 times and then it would start. Otherwise it would just crank and crank for a while and then start. Pretty embarrassing! Took it to the dealer and they said that my fuel pump was losing pressure. I changed the fuel pump and I don't have to prime the pump anymore.
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no check engine lite on ...so could it be a map sensor, idler air sensor, or if it was a crank shaft sensor would it not cause the engine to shut off? there is no sign of any smoke come out of the tailpipe and no sign of water in the oil.
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