2002 Jeep Grand Cherokee Laredo – Stalls at Slow Speeds
Reader Question: I have a 2002 Jeep Grand Cherokee Laredo v-6. When I am idling at a light, my jeep has shut off about seven times. It starts right back up though.
When I am idling and sometimes while driving my car will rev up and the RPMs go up and then back down to normal. It feels like the jeep is trying to shut off but then the RPMs go way up to stop it from shutting off.
I went and put it on a computer at a local auto zone and the problem that came up was the throttle sensor. I also went and had a fuel injection cleaning at my local oil change place and when they were doing it, a bunch of white smoke came out of the tail pipe. I was told this was good that it meant the fuel injectors were very dirty.
I was hoping this would be the answer to my problem. However, unfortunately not, the next day it started acting up again.
My question is – do you think the bad throttle sensor could be causing the car to shut off like this? The part is US$75 and then I need to pay someone to install it so I am wondering if I should spend the money or it was suggested by a couple of people that I possibly could use a tune up, which I know is good to do anyways but I am trying to fix the problem at hand.
In addition, the check engine light has been on for a long time but when I read the manual initially, it said that this light came on and it meant I had put some bad gas in.
Please help me with any information you think I need!
Thanks so much,
Lauren
Hey Lauren,
If the check engine light is on, I would definitely spend US$75-100 to have your computer codes read by a real mechanic; not at Auto Zone…they are great for buying parts but not for diagnosing computer related problems.
You could very well have a TPS – Throttle Position Sensor problem, but this problem could be caused by many other issues as well, so before I guessed at a US$75 part I think I would have someone look into it further.
A dirty throttle body and idle speed motor can cause a common idle surging and dying at low speed complaint, which is part of the fuel injection system. Your local oil change guys may or may not have cleaned the throttle body and idle speed motor when they did the “fuel injector cleaning”.
Although a dirty throttle body and idle motor will cause dying and idle surge complaints like you mentioned it will usually not cause the check engine light to come on.
The check engine light is continually coming on due to a consistent problem your onboard computer is seeing when it performs its self-tests. One of the man emissions control sensors is usually the culprit of a yellow check engine light being on. A drop in fuel mileage and engine performance can sometimes accompany a yellow check engine light being on.
Needing a tune up could cause poor engine performance, but you did not mention anything about the engine running bad OFF idle so I do not think you need to get a tune up to correct this problem and I really doubt you have a “bad gas” problem.
Here is more about the throttle body and idle motor on my blog:
Blessings,
Austin Davis
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Also check the Mass Air Flow (MAF) sensor, located after your air cleaner and the throttle body. It’s just before your Idle Air Control Sensor. Same idea is to clean it with throttle body cleaner, brake cleaner, or electronic contact cleaner. Causes the same issues on multiple makes and models. Had the same issue with a 4runner after driving on a dusty road. If you clean it, and it doesn’t fix the issue, try to unplug the unit. You will get a Check Engine Soon light, but you may notice that the engine runs better. If so, replace the MAF sensor. Its a cheap test you can do at home, and easy to fix if it’s the problem.
Cheers,
Jay
my 2003 jeep has 180,000 miles on it and it is shifting out hard when i drive it.
Could be low on transmission fluid? Could be the engine idle speed is set to high? Could be an internal transmission problem? Rule out first two then have a transmission shop drive it with you to get their opinion. they do make some additives that will calm down harsh shifting, but with that many miles I would highly suggest you talk to the transmission shop first before you use one. Lucas products makes a good one, and so does Wynns.
I’m having a problem for about six months, changed bunch of things on my 1995 grand Cherokee (4.0) and still nothing. Maybe someone can give me an answer here:
when I start my jeep everything is normal :), about 700 RPMS. But as soon as the engine warms up it goes to 1000 (in drive), 1100-1200 (in park or neutral). Changed Throttle position Sensor, Idle Air Control Sensor, recently did a tune up (spark plugs, wires all filters…), installed new catalytic converter, changed oxygen sensor. Went to many different mechanics, nobody did anything.
The Jeep gives me now poor mileage…
SUCCESS!!!! I Have discoverd The Answer to Everyones Problems! (well those that are having the same high RPM Issue) The problem is as simple as this: The Air Idle sensor (conected to your throttle body) Is VERY dirty and has carbon build up on it. The Solution: disconnect all three sensors attached to your throttle body,take off your throttle body by removing the 4 bolts to the intake manifold, unscrew the two HEX head screws from the Air idle Sensor connecting it to the throttle body, Then use Break cleaner/throttle body cleaner to clean off the surface of the sensor until its nice and shiny, also clean the port connecting the sensor to the throttle body (remove it by unscrewing the 4 ALLEN head screws connecting it to the throttle body). put it all back together, start up your Jeep, let it run for 5 min, take it for a little jaunt, turn it off again, then back on, and then enjoy not listening to the VROOM VROOM of the engine when you start it up!
went to the mechanic today…. He tried everything and COULD NOT figure out what the problem is. He said my intake is Great, no Vacuum leaks or anything. plugged it in to all the computers and no codes came up, all the sensors read just fine and the throttle body was clean. I NEED TO KNOW WHAT IS WRONG WITH MY JEEP
It only started acting up after i installed a performance air intake kit, and im pretty sure a fuel pump wouldnt cause the RMP boost at start up…. i dont have any codes showing up because i dont have a check engine light on
Then I would remove the air cleaner and replace the original one
I am having the SAME EXACT issues with my 2003 Jeep Grand cherokee 4.0L. i have 79k miles and when i start it up it goes to 1.8k-2.2k RPMS and Idles there for a little while before resting at around 700-1100RPMs. and along with the Highway issues, im having those same issues as well, no power whatsoever after 35MPH. Its as if it never wants to down shift. if its a fuel pump or TBS thats great easy fix, i just want to get it taken care of.
It could be a faulty fuel pump but I would want to read your onboard computer codes and test the fuel pump pressure with a manual pressure gauge before replacing the pump which is pretty costly.
I have a 2002 laredo jeep and it has about 97000 miles on it. it seems as if “nothing” is wrong with it however similar to some stories i have seen online. when i crank the jeep, it revs high 2.5-3K sometimes. and if you dont let it sit and warm up it slams into reverse. i live in FL and its not like the truck is freezing before i leave. sometimes it takes over 10 minutes to get the idle back down.
with that being said, it drives great and doesnt seem like it slips and i have been told that there is nothing wrong that any car will do that when its cold. i have had my share and i have NEVER had a tranny slam so hard into reverse. and if im just sitting there, it revs up and down.
if im getting on the interstate, it goes good until about 50mph where it goes into its final gear where there is no “down shift” to make it get up and go. there is no power what so ever at 50-60mph which im being told at the dealership (not jeep) that there isnt anything wrong.
everyone says the same thing, nothing is wrong. i wanted to move to TX from FL but im scared that it wont make the drive with whatever is happening. i dont even know where to start.
any ideas? do you think it could be this throddle sensor? i know im not crazy and there arent any lights on saying there is an issue but i know that there is something and no one can tell me what it is.
help??
We had a customer in my shop years back with the same vehicle and same problem….and they seemed to think things were fine so we did not “repair” anything but I was shocked that it would idle so high for a few seconds, but they were not concerned.
I would visit the Jeep dealer again and talk to another service manager. I think you DO have a problem…maybe a throttle position sensor, maybe a dirty throttle body, maybe a problem with the fuel pump…I am not sure but I agree with you, something is not right. If you dont have any power at freeway speeds it would lead me to believe there could be a lack of fuel pump pressure.
Sorry I cant really help you more. I hope you can find a mechanic who will spend a little time investigating this for you….and let us know what they come up with.