2000 cherokee sport 4.0 hard cold starts and rough idle

long post.
ill reduce it for you.
misfires. (is RPM below 700 then misfire can be normal) for idle speed controls dead.
ISC the isc controls speed, of idle,.
mine stuck like zillion times, in 400k miles. endless.sticking
mine was a tiny gutless stepper motor drive ISC valve.
the cone valve is side gets nasty and sticks (
(PCV gases caused as seen on all engines)
i clean it.
the proof is the easy press of right foot easy raises idle back to 700rpm and engine stops misfiring.
ever get a tuneup this decade or running spark parts 500,0000 miles
for the new world record.?


now the tricky part of ISC, , fully explained in the SM serv. man.
the PCM learns its behaviors.
it learns all hot start settings and cold
so when you key on, it goes to the correct HISTORICAL spot.
if it can move there(sticks) engine car race.
or run too slow,
cold start would be worse, as hot isc is more closed
so if sticks there closed, the next cold start will be horrid
some newer manuals telly you to add 5% throttle if car is hard starting this is so common.

clean it. end story.
ISC

sounds like blown headgasket

If your check engine light illuminates when the jeep is running bad, have the trouble codes read to find out what exactly is the problem. I would guess and say it's the heating element, of the O2 sensor, that is bad and causing hard starts when cold.

If you have a check engine light on do diag. see what code's you have, also do a cylinder compression test that will tell the story.Good luck

Have a fuel pressure test done, that will show if the fuel pump is weak, or the fuel pressure regulator is faulty.

It sounds like its out of time move the distriutor a little bit

could be rod with that amount of miles

My 2000 Grand Cherokee had the same problem, without all the sputtering, it would just die approaching a stop. We could only keep it running by slightly pushing down on the gas petal when coming to a stop. I replaced the Throttle Position Sensor, but that didn't change anything. A new mechanic I found replaced the Idle Air Control Valve, and we've had no problems in a week.