I have seen a lot about the 4.0 stalling but not as much for the 5.2. My jeep runs great, no issues when it's running but it just started stalling on me tonight. I noticed today when I would start it, it would almost die but pick rpms up on it's own. Now tonight on my way home from work it stalled on me twice. RPMS drop down at idle and they drop too far to the point where it dies. Where should I start?
Sounds like a dirty IAC if it stalls while idling. Start there, it takes five minutes to do. Two T25 torx bolts on the back of the throttle body. Clean it with some carb cleaner but don't push the spindle in and out while cleaning. Clean inside where it mounts and clean the intake while you're already there.
Does it start right back up after it stalls? What maintenance have you done recently? Could also be a dying fuel pump or failing PCM. Wiggle the three harnesses that plug into the PCM while running, any change in idle is bad.
Thanks, I'll try that tomorrow. Only thing I have checked so far since it's dark out is the battery cables. They are good and tight. It will start up fine but some times it will drop rpms down so much that it will die. Sometimes it will drop rpms down but not enough to kill it, then the rpms come up a little to the normal idle and idles just fine. If I rev the engine up once I let off the gas the rpms drop down too far and it dies.
Fyi get a box of Q-tips and some carb cleaner... spray the qtips with the cleaner and where the IAC was sitting in... clean that.. itll take like 20 q-tips to clean that really good.. Then get a rag and wet it with the carb cleaner and open the butterfly on the throttle body and clean all around inside... If the gap gets full of carbon your idle will be high... My friends 5.2 was stalling and after I cleaned the IAC and throttlebody it hasn't done it since..
Just don't twist the nipple on it when you clean it
2013 6.2 V8 Camaro SS 9k miles
1998 5.9 V8 ZJ 180k miles
1998 4.0 I6 Laredo ZJ 227k miles
Ok, cleaned the IAC and no luck. Started up fine this morning like nothing was wrong. Cleaned it off, was running great so I took it for a drive to warm it up. Thought we were all good and I got home, gave it some gas to get up the hill behind the house and as soon as I let off the gas it died. Now with it warmed up I start it, and then it dies, start it, then it dies. If I give it some gas right away and I let off the pedal easily then it will stay running fine. I'll pull it apart again and do what Candymancan says and see if that helps. Should I seafoam it?
Seafoam will clean up the injectors and combustion chamber but won't magically fix the problem. It sounds like fuel starvation. Are you getting any engine lights? Ever replace the upstream oxygen sensor? Did you wiggle the PCM harnesses while idling?
haha sorry Jason, apparently I didn't completely read your post because all I did was clean the IAC, I didn't clean inside. Then I saw his post about using the q tips inside and I did it. You both were correct, I was the moron who could have had it fixed sooner if I did step 2 of what you told me to do in the first place! haha, thanks guys.