How to fix a Jeep that keeps stalling out
The stalling problem
Many, many people have complained about their Jeep stalling out for no apparent reason. Usually, this happens in a LOW IDLE situation where your RPMs are low - for example, a red light, or worse yet, during stop and go traffic during rush hour!
I too know your pain. My 2003 Jeep Grande Cherokee (Laredo) also joined the club of stalling vehicles. At first, the stalling is slight, more of a hick-up in the RPMs when sitting at a light, or idling in traffic. Over time, the problem gets worse, the RPMs run lower and as soon as you see the red light in the intersection you fear that, yet again, your jeep will stall out. It doesn't matter if the engine is hot or cold, it stalls! After it stalls, you try to restart it, but it won't turn over - until finally after sitting for a few minutes it starts again.
The biggest problem I faced, was the irregualrity of the stalling issue. I brought my jeep into the dealership a number of times, but of course, it had time to sit in the parking lot for a few minutes and when they fired it up and plugged it into their diagnostics, no problem was ever found.
1. Get under the hood and remove the air intake on top of the engine. Clean the Air Intake manifold with an aerosol cleaner (purchased at any auto store). You will probably see that years of gunk and dirt are built up in there. Squirt some cleaner into the little opening on the side of the air intake wall. This your Idle Air Control, and again, dirt and gunk can be clogging your sensor and motor.
2. Now that things are clean and shiny, see if that solves the problem. For some, it might just be a case of a dirsty sensor not reading right. In my case, it wasn't.
3. The real issue, if stalling continues, is your Throttle Position Sensor. It's a cheap part to fix as it sits right on top of the engine. When this sensor doesn't read right, the engine is not getting enough, or is getting too much air. This is causing you engine to hick-up and stall out. Its tricky to diagnose as most mechanics hook your jeep up to a computer, and when the engine is working fine, nothing appears on their diagnostic software. Only if your jeep stalls out, while hooked up to the diagnostic, will the problem ever be seen. I recommend going to a mechanic as the screws likely need correct torque for the sensor to work correctly. I got mine replaced (with installation) for just under $200.00.
The Jeep Now:
Since replacing the Throttle Position Sensor, the jeep has run perfectly!