Hi friends. I have a Puzzler-worthy issue going on with my 2002 Jeep Liberty (LTD, 4WD, V6). A few weeks ago (Christmas Eve!) it started to stutter when slowing down to a stop, and then – after a few times of doing that – began the bigger problem of completely stalling out/shutting off once at a stop (in traffic, at a light/stop sign). It starts up fine and idles fine from a stopped position; it’s only when I drive and slow down and come to a complete stop that it has the issue. The shop I go to is a great Jeep-based shop, and they’ve:
serviced the (quality, few-year-old Interstate brand) battery. Initially, it was a bit drained, but they charged it up and made sure nothing else was draining it. I went to drive it home but it had the issue, so brought it back.
cleaned the idle control sensor. They found it was a bit gummed up, affecting airflow under 10MPH. Said that did the trick for them with multiple test drives but then I went to drive it home last night and it did some stuttering on the way home when I started coming to a stop. I tried not to get frustrated; “Maybe it’s going to stutter a wee bit now and then,” I thought. “No complete stall-outs = good.” But this morning driving to work it stalled out nearly every time I came to a stop. I took it back in and they’re going to keep investigating.
The issue is a bit frustrating since we had just gotten a major engine repair around $3500 due to coolant leaking into the engine (the heat wasn’t working and that was apparently why). We figured $3500 was still worth at least 5 more years of driving (the car has ~120K miles) rather than start looking for a new or new-used car for 3 or 4X that price. But now this.
Any ideas welcome; I trust Golden Gate Jeep but figured I’d put it out there for any ideas or just plain Puzzler enthusiasts
The stalling might still be caused by a faulty Idle Air Control valve.
To find out if it is, the next time you come to a stop, while braking with your left foot, slightly step on gas pedal with your right foot. If doing this prevents the engine from stalling, replace the IAC valve.
Has anyone cleaned the throttle plate in the intake plenum? You can do this yoursell bt taking off the tube from the air cleaner to the intake plenum,and spraying or brushing carb cleaner. fuel injector or intake cleaner on the throttle plate and surrounding area. Wipe it out with clean rags
They cleaned the throttle body already. I’m with Tester if its stalling regardless of the car being in gear or not. If it is stalling while in gear and feels like a manual trans would with the clutch not pushed in, I’d suspect the lock up torque converter as my2cents mentioned.
Thanks so far, everyone! The update is that they replaced the idle control sensor and it’s still doing it. I’m not sure if that’s the same exact thing as the idle control valve, but I know they’ve been all over the whole idle-control-everything so I’m going to trust they have worked through that area. When I spoke to them today, they’re looking into possible electrical-system issues (even a minor wiring issue might be at play?) But it sounds like the main remaining idea from this comment thread so far (thanks, Tester!) is that the lock-up torque converter clutch is being problematic (not releasing when come to a stop). I’ll run that by them to throw it in the bag of things to keep exploring.
Any other ideas, reactions, or comments keep 'em coming!
You can test if its the lock up torque converter by simply putting the car in neutral when coming to a stop to see if it still stalls or not. Putting it in neutral disconnects the transmission from the engine.
Do you have an rpm display on the dash? If so, what’s it saying? If not, one idea, ask them to hook up a temporary one for you to monitor. The engine will have a spec for idle rpm, and if your engine isn’t meeting that spec, that would be an important clue.
If this only happened when the engine was cold, or the weather was cold, that could provide a clue. Anything like that?
I expect you already know this OP, but for drivability problems like this the first step is to query the computer’s memory for any diagnostic codes stored there. And address those that could be related to this symptom first. The second step is to review the routine maintenance that’s been done on your car, focusing on things that have been deferred and are now behind schedule. Either in time or miles. You don’t want to pay a shop to diagnose something that could be fixed just by changing the spark plugs and air filter per the owner’s manual routine maintenance intervals for example.
Tester , I will concede that however a fuel filter full of water can cause many erratic behaviors when the engine gets a slurp of water (been my experience with diesel trucks over the years )
When a person starts throwing parts ,start with the cheapest first .
I’m experiencing this same issue with a 02 Liberty that is still at the dealership. Technically I bought the thing but haven’t yet taken possession of it because it stalled on my test drive when coming to a stop. The RPMs drop briefly halfway between 1 and 0 with a stutter when it manages to stay running. They’ve “cleaned” the throttle body sensor or something, but today I took it on a second test drive and it stalled a couple more times. The latest is that the shop put on a new Idol Control sensor. The salesman took it for a drive and tells me he can not replicate the stalling we experience on the test drives. Not sure if I can trust them at this point. Has the original poster or his thread gotten her own issue solved? If so, what was the cause of the stalling?
There’s a lot of things that can cause stalling like that, some very expensive to diagnose and repair, so be sure the problem is 100% solved before writing any checks. The idle air control valve (or “motor” or “actuator”) is a pretty common cause to that problem here on many vehicles, not just Liberties.
Not sure what part that is. The only sensors involving idle speeds I can think of, one is in the valve described above, and the other is the crank position sensor.
Note that this vehicle probably goes through a learning mode if the computers are ever reset, for example as might happen when replacing the battery. When that happens it may take some driving time for the computer to relearn the idle parameters.
The problem with that is that I already paid them for the vehicle with the guarantee that the problem would be fixed. Stupid move on my part, I know. Now that the Liberty has been in the shop a couple time, and the cost of repairs is going up for the dealership, it’s going to be a bit of a fight to get my money back.
