96 Grand Cherokee Stalling

I have a 96 Jeep Grand Cherokee Laredo, 6 cylinder, automatic with
about 160000 miles. Over the past several weeks, it has developed an
annoying habit of stalling. Initially, this only happened when stopped
at a traffic light or stop sign. It would begin to stumble and then
stall. If I shifted into neutral, and gave it some gas, it tended to
not have the problem. It wouldn't do this at every stop, and typically
only did it during the first 15 minutes of driving. When it stalls, it
will usually start back up right away, though sometimes I have to try
to start it 5 or 6 times before it will actually start.

More recently, it has began to stumble and hesitate briefly even at
highway speeds, though this is far more rare than the stalls when
stopped. Sometimes it will happen after pulling away from a stop: it
will stumble, cough and sputter, and if I give it some gas sometimes it
will recover and go on about its business. Needless to say, all these
stall outs in rush hour traffic can be pretty unnerving.

After reading about similiar problems with JGCs of this vintage, I've
tried the following:
1) Changed the ignition coil: This had no effect on the problem.
2) Changed the fuel filter: It ran great for about 35 miles, leading me
to think I'd solved the problem, then it stumbled and stalled in a
traffic stop, and misbehaved on and off for the next 5 to 10 minutes.
@#%$

I fear it's the fuel pump, but given that it usually starts back up
pretty quickly (i.e., a few tries) after stalling, I'm not sure. After
it has one of its coughing/sputtering/stumbling/stalling episodes, it
does set engine code 43.

I've read a lot about problems with bad CPS's. Any thoughts?

P.S. I'm taking it to the dealership on Wednesday morning to get the
PCM reprogrammed and my catalytic converter replaced under the recent
E22 emissions recall. My converter has been rattling around for over a
year. Nice of them to replace it for free. :-)

Thanks,
Doug

Hi Doug,
You didn't mention the basic maintenance like spark plugs in the
last twenty thousand miles: http://www.billhughes.com/lubeSchedule.pdf
May be your throttle Position Sensors, and/or Idle Step Motor need
to be cleaned: http://members.cox.net/wilsond/tb/tb.html
God Bless America, Bill O|||||||O


wrote:
>
> I have a 96 Jeep Grand Cherokee Laredo, 6 cylinder, automatic with
> about 160000 miles. Over the past several weeks, it has developed an
> annoying habit of stalling. Initially, this only happened when stopped
> at a traffic light or stop sign. It would begin to stumble and then
> stall. If I shifted into neutral, and gave it some gas, it tended to
> not have the problem. It wouldn't do this at every stop, and typically
> only did it during the first 15 minutes of driving. When it stalls, it
> will usually start back up right away, though sometimes I have to try
> to start it 5 or 6 times before it will actually start.
>
> More recently, it has began to stumble and hesitate briefly even at
> highway speeds, though this is far more rare than the stalls when
> stopped. Sometimes it will happen after pulling away from a stop: it
> will stumble, cough and sputter, and if I give it some gas sometimes it
> will recover and go on about its business. Needless to say, all these
> stall outs in rush hour traffic can be pretty unnerving.
>
> After reading about similiar problems with JGCs of this vintage, I've
> tried the following:
> 1) Changed the ignition coil: This had no effect on the problem.
> 2) Changed the fuel filter: It ran great for about 35 miles, leading me
> to think I'd solved the problem, then it stumbled and stalled in a
> traffic stop, and misbehaved on and off for the next 5 to 10 minutes.
> @#%$
>
> I fear it's the fuel pump, but given that it usually starts back up
> pretty quickly (i.e., a few tries) after stalling, I'm not sure. After
> it has one of its coughing/sputtering/stumbling/stalling episodes, it
> does set engine code 43.
>
> I've read a lot about problems with bad CPS's. Any thoughts?
>
> P.S. I'm taking it to the dealership on Wednesday morning to get the
> PCM reprogrammed and my catalytic converter replaced under the recent
> E22 emissions recall. My converter has been rattling around for over a
> year. Nice of them to replace it for free. :-)
>
> Thanks,
> Doug

Hi Bill,
Well, the spark plugs are certainly "vintage". But given the
intermittent nature of my problem, and the fact that it can also happen
to some degree at highway speeds, would you think the plugs and/or a
dirty throttle body would be the root cause? I'll certainly try
dropping in some new plugs and cleaning the throttle body. Can't hurt.

Thanks,
Doug

Bad plugs will bark back through the intake destroying the step
motor and any vacuum diaphragms.
God Bless America, Bill O|||||||O
http://www.billhughes.com/

wrote:
>
> Hi Bill,
> Well, the spark plugs are certainly "vintage". But given the
> intermittent nature of my problem, and the fact that it can also happen
> to some degree at highway speeds, would you think the plugs and/or a
> dirty throttle body would be the root cause? I'll certainly try
> dropping in some new plugs and cleaning the throttle body. Can't hurt.
>
> Thanks,
> Doug

dougguitar wrote:

> 2) Changed the fuel filter: It ran great for about 35 miles, leading
> me to think I'd solved the problem, then it stumbled and stalled in a
> traffic stop, and misbehaved on and off for the next 5 to 10 minutes.
> @#%$

That is telling you something.

Take your nice new shiny filter off.
Put your fingers over the holes and shake it.
Turn it input side down over a glass and see what comes out.

You might have a tank full of crapoline
http://revbeergoggles.com/badgas/

I have gone through three filters to get the last load
out of the tank.. but usually they clog after a few thousand
miles.

--
DougW

Staling when cold with it stumbling at other cold times implies a dirty
connection on the TPS or throttle position sensor. Ours acts like that
when dirty anyway.

I recommend using a spray contact cleaner that electronic stores sell on
all the plugs and sockets on the throttle body. It can't hurt and that
fixes ours.

There is also an idle air passage that can get carboned up and need
cleaning, but that usually just stays as a bad idle.

Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
88 Cherokee 235 BFG AT's
Canadian Off Road Trips Photos: Non members can still view!
Jan/06 http://www.imagestation.com/album/pi...?id=2115147590
(More Off Road album links at bottom of the view page)

wrote:
>
> I have a 96 Jeep Grand Cherokee Laredo, 6 cylinder, automatic with
> about 160000 miles. Over the past several weeks, it has developed an
> annoying habit of stalling. Initially, this only happened when stopped
> at a traffic light or stop sign. It would begin to stumble and then
> stall. If I shifted into neutral, and gave it some gas, it tended to
> not have the problem. It wouldn't do this at every stop, and typically
> only did it during the first 15 minutes of driving. When it stalls, it
> will usually start back up right away, though sometimes I have to try
> to start it 5 or 6 times before it will actually start.
>
> More recently, it has began to stumble and hesitate briefly even at
> highway speeds, though this is far more rare than the stalls when
> stopped. Sometimes it will happen after pulling away from a stop: it
> will stumble, cough and sputter, and if I give it some gas sometimes it
> will recover and go on about its business. Needless to say, all these
> stall outs in rush hour traffic can be pretty unnerving.
>
> After reading about similiar problems with JGCs of this vintage, I've
> tried the following:
> 1) Changed the ignition coil: This had no effect on the problem.
> 2) Changed the fuel filter: It ran great for about 35 miles, leading me
> to think I'd solved the problem, then it stumbled and stalled in a
> traffic stop, and misbehaved on and off for the next 5 to 10 minutes.
> @#%$
>
> I fear it's the fuel pump, but given that it usually starts back up
> pretty quickly (i.e., a few tries) after stalling, I'm not sure. After
> it has one of its coughing/sputtering/stumbling/stalling episodes, it
> does set engine code 43.
>
> I've read a lot about problems with bad CPS's. Any thoughts?
>
> P.S. I'm taking it to the dealership on Wednesday morning to get the
> PCM reprogrammed and my catalytic converter replaced under the recent
> E22 emissions recall. My converter has been rattling around for over a
> year. Nice of them to replace it for free. :-)
>
> Thanks,
> Doug

DougW wrote:
>
> That is telling you something.
>
> Take your nice new shiny filter off.
> Put your fingers over the holes and shake it.
> Turn it input side down over a glass and see what comes out.
>
> You might have a tank full of crapoline
> http://revbeergoggles.com/badgas/
>
> I have gone through three filters to get the last load
> out of the tank.. but usually they clog after a few thousand
> miles.
>
> --
> DougW

Well, when I changed the old filter (which had been in place far longer
than I'd like to admit), I was a bit surprised at the dark brown goo
that poured out of the inlet side of it. However, this has been going
on for a couple of months now (happening more and more often), so if
it's crapoline I must have an uncanny knack for finding it. I usually
fill up with cheap gas at Walmart/Murphy, so maybe...

A new wrinkle to add this morning: After driving about twenty minutes
this morning, I stopped the vehicle to go in and run an errand. Came
back out about five minutes later, and it didn't want to start. This is
a first. I've never had a problem with a "cold" start.
It would crank fine, of course, but not start. After about 2 to 3
minutes of trying, it did finally start. If it does this again, I'll
tap the fuel pressure valve and see if it has pressure.

Solving this mystery would be fun if it weren't:
A) An expensive pain in the butt, and
B) leaving me stalled out in rush hour traffic frequently. Most of the
time it idles and runs fine. But these random problems always occur at
the worst time. :-)

Thanks for all the suggestions, guys. Hopefully, I'll have time to nail
it over the long weekend.

Doug B.

If you happen to be low on gas this would be an opportune time to drop the
tank and clean the gunk out of it.

You have to remember that it, most likely, isn't just crapoline from one
tank fillup but many (unless that load was particularly bad).

FWIW I got a tankfull of bad Shell gasoline back in the earlier '80s but
that Shell station pretty much told me to 'drop dead creep' when I asked
about a refund. After I drained out the 20 gallons and replaced it with
some Chevron from the lawn mower gas can and a new $1.99 filter it fired
right up.

I've only bought gas from Shell a few times in the intervening 20+ years...
not that they miss my business all that much. That particular station might
have.... I got 20 gallons three times a week (100 mile round trip to work)
and the business went to the Chevron directly across the street.

> wrote in message
ups.com...
>
> DougW wrote:
>>
>> That is telling you something.
>>
>> Take your nice new shiny filter off.
>> Put your fingers over the holes and shake it.
>> Turn it input side down over a glass and see what comes out.
>>
>> You might have a tank full of crapoline
>> http://revbeergoggles.com/badgas/
>>
>> I have gone through three filters to get the last load
>> out of the tank.. but usually they clog after a few thousand
>> miles.
>>
>> --
>> DougW
>
> Well, when I changed the old filter (which had been in place far longer
> than I'd like to admit), I was a bit surprised at the dark brown goo
> that poured out of the inlet side of it. However, this has been going
> on for a couple of months now (happening more and more often), so if
> it's crapoline I must have an uncanny knack for finding it. I usually
> fill up with cheap gas at Walmart/Murphy, so maybe...
>
> A new wrinkle to add this morning: After driving about twenty minutes
> this morning, I stopped the vehicle to go in and run an errand. Came
> back out about five minutes later, and it didn't want to start. This is
> a first. I've never had a problem with a "cold" start.
> It would crank fine, of course, but not start. After about 2 to 3
> minutes of trying, it did finally start. If it does this again, I'll
> tap the fuel pressure valve and see if it has pressure.
>
> Solving this mystery would be fun if it weren't:
> A) An expensive pain in the butt, and
> B) leaving me stalled out in rush hour traffic frequently. Most of the
> time it idles and runs fine. But these random problems always occur at
> the worst time. :-)
>
> Thanks for all the suggestions, guys. Hopefully, I'll have time to nail
> it over the long weekend.
>
> Doug B.
>

Maybe the cat is going bad.

Later Mike

Mike chambers wrote:
> Maybe the cat is going bad.
>
> Later Mike

Oh, the "cat" is definitely bad. It's getting replaced for free in the
morning via a recall notice DC just put out on my Grand Cherokee. It's
been rattling like a box full of cans tumbling down a staircase for
about a year now. Sometimes procrastination pays off.

I'm off to get contact cleaner and spark plugs.

Doug B.