Car Tech forum: 97 Jeep Grand Cherokee Laredo keep dying upon ignition

Mine is a 97 GC Laredo with 4.0 eng / 6 cyl and 2 wheel drive.
It hesitates and then dies after driving about 10 to 15 minutes.

If I wait about 15 minutes it will start again and then repeat
the dying. So for I have replaced the 3 yr old battery and spark plugs & wires. It started running smoother with the new wires and plugs but still does the dying routine.

I suspected a fuel system related issue but after reading the
experiences other owners have had it sounds like the fix could be all over the chart from sensors to catalytic converters to and about another dozen parts mentioned by others.

From the symptoms I described does anyone have ideas on narrowing it down a bit. Thanks for any help. Damian007 you have been above and beyond helpful. Thanks.

Reference:
1997 Jeep Grand Cherokee Laredo, 4.0 engine with 2 wheel drive and currently at about 115,000 miles.

Mine kept dying especially when in stop and go traffic.
Usually it would start back up. I had to have it towed once.
The problem got progressively worse and I just did not trust it
to drive very for from home as it was dying on every outing.

A very good mobile mechanic in my area that drives out to your site
figured out it was the PCM (Powertrain Control Module) that some have also have referred to as ECM (Electronic Control Module)

On my Jeep it is mounted under the hood of the firewall (passenger side). It is beside the Coolant Overflow Reservoir which had to be removed to get to the PCM.

The mechanic could jiggle the wiring harness on the PCM and the Jeep would die. Now that it is replaced it has been running great for 3 days. So for so good. I hope that fixes it for at least 85,000 more miles. He kindly gave me his discount price on the part so $300.00 dollars later my Jeep is good to go.

He had to make an extra trip to the parts store since the first PCM
we got from them (of course they are all remanufactured) was so poorly done it had a crack at the top and was simply unacceptable
so he returned it for another and the re-mfg job on it looked pretty sloppy itself but everything looked intact. Do they have some kindergarten classes remanufacturing these for school fund raisers? A part this expensive you sure expect better.

I am glad he quickly figured it out as reading the dozen or so different parts that others have replaced had me thinking it was time to get rid of my Grand Cherokee.

I have liked my Jeep and realize it is now 12 years old but 'good grief' I am not impressed with Chrysler's attention to quality control from the time period mine was built. Have they gotten any better 12 years later? I wouldn't want to pay the price on a new one to find out and when I looked at the mileage figures on a new Grand Cherokees 12 years later they only are about 2 miles or so per gallon better than my 1997.

Again 'Good Grief Chrysler" and the rest of the US auto manufacturers. Get your act together!

Hell, your maybe $400/600 to include a reflashed PCM... and

To sell it now, when it is not running... will cost you alot more then $400.00. You'll be lucky to get a $1000.00 for it as is,... if that, unless you trade it in for another car.

Your toasted either way... at this point, might as well fix it and sell it for full value

Good luck and I hope the PCM replacement solved your problem. I'm trying to solve mine with zip ties. (search on my name to see my posts).

The flickering dash light is due to a poorly designed headlight switch unit (about $125 OEM). You're right about it being an irritant, but it's far from serious. I bought a used one off EBay for my 98 GCL and I got what I paid for. They must develop a short or something.

Yes, I had a problem like that, I just posted the fix today. What I find out after I had replace the cranksor and various other parts was I had crack in the exhaust manifold. Make sure before you go spending money that your exhaust system is air tight and O2 sensor are receiving proper engine exhaust data before you start replacing stuff.

oK i have a 1996 jeep grand cherokee laredo.
i just bought it off someone knowing it had this problem
anyway. the car stalls! randomly. i'll be driving up a hill and it will stall or on a straight away and it still stalls. it will take anywhere from 5 min to and a half hour or more or less or w/e to start back up!.. nobody seems to be able to help with this? what can i do? some help pleasee.

any ideas??...

thanks for replying!.
yeah i have a mechanic and he looked it over for a while..
and kept it running and it wouldnt stall for him!.. but he'd found a wire that wasnt grounded that could have been causing it to stall.
and he changed the spark plugs and stuff like that. now on the iginition coil there was a wire coming out of it that didnt connect to anything which was probably the same wire that he found but im not positive; my brother found it and was playing with it and when it touched certains parts under the hood it caused the car to stall
so we taped the wire to something so that it wouldnt come in contact with anything.. but then it stalled again; but i figure that was cause maybe the ignition coil is somehow getting like damaged or fryed? im not a mechanic, obviously.so i went to jeep yesterday and he says that the wire coming from the ignition coil didnt goto anything and to remove it. my car stalled again and i disconnected it near its beginning, and my car started like 10 min later or so. do you think a faulty iginition coil could be causing this to happen?

ok here we go. first of all o2 sensors on all obd II jeeps (96 and up) DO read oxygen content at idle (once in closed loop mode) it uses this info to adjust short term adaptive memory and long term memory which basicly is fuel mixture. the only time the o2 sensor is ignored is in closed loop, wide open throttle or a severe missfire.anyway,this doesnt appear to be your problem since youve already replaced them. although a o2 sensor shorting out internally or externally on a jtec (jeep truck engine controller) engine can cause the engine to stall and not set a dtc. this is due to a design flaw in this controller. what happens when almost any of the engine sensors on this jeep has a short it temporarilly zapps the pcm (jtec).when this happens the controller losses all power and memory therefor no dtc is set. this is what makes it so hard for jeep techs to figure this problem out. so yes any of the sensors shorting out internal or external can cause a intermittant stalling on jeeps. now the next thing that can cause a stalling concern on jeeps is yes the iac motor being dirty but remember the iac only controlls the idle is when you are not pressing the gas pedal. also a weak battery will cause the pcm to loose the iac minimum set memory.there was a software update on some of the jeeps to address this. now to really get out there there has been some high milage 96-01 jeeps with this exact concern but you will also have alot of weird things going on with the instrument cluster and lighting. chrysler engineering is supposed to be investigating this issue. dont ask how i know this. but you might want to check the drivers and passenger door control switches these switches are actually modules drivers door and passenger door module. these modules communicate over the vehicles bus (communication line). if one of these modules is shorting out it could be confusing the pcm. the pcm might be getting a false signal due to this short and thinks that the theft alarm has been triggered even if it is not eqquiped with vtss from the factory. you can unplug these modules one at a time and drive it and see if your problem goes away. ive seen some of these be very obvious because when you go to unplug the module the connector will be slightly or severely melted.remember the pcm is looking for what is called a mux (multiplex) signal. mux is just a voltage signal it can be .1 volt or up to 5.0 volts to control various vehicle functions including the vehicle theft security system (vtss).so a funky voltage change that goes over the bus can cause some strange things.

It's interesting to note that my 1996 JEEP is ODBI Not OBDII. I have no modules or can bus on my vehicle. Also my Factory Security does not disable the Ignition or Starter Motor. I have the JEEP LIMITED which is the Luxury model in this country. I do know, However that the 98 JEEP is OBDII. So, My question is, why would JEEP keep the OBDI in this country when yo say that all 96 JEEPS are OBDII Compatible? I am just wondering if you are right in what you say..

I'll try and help you with this one. 98 JEEPs have Anti-Theft. There is a transponder in the Key. If the Anti-Theft doens't see the right transponder, vehicle won't go. The reason I say this is that you mention a little red light comeing on. Also check that the ASD Relay hasn't been tripped. I think you'll find this relay under the Hood on the Passenger side. You know it by the heavey Wires going to it. it also sit's there on the inner guard on it's own. It's worth looking at. Good Luck and let me know what you find.

I have been having a problem similar to everyone else. I have 1997 Jeep Laredo and it ran fine at first then I had a fuel pump problem, then it started this new probem. I will be running along and it will be fine and then it bogs down like it is going to die, sometimes it does, sometimes it doesn't. When it does die sometmes it will not restart and I have to wait (usually several minutes) or it won't start at all and I have to have it towed or wait til the next day and then it will start. It doesn't send any signals, no lights on the dash, no other power loss. I have had it with my mechanic several times and he hates it as much as I do. We've replaced the coil, wires, pins, rods, and several other things that I don't even know. He assures me it is an electrical problem and he wantS to replace the harness. Although from reading what everyone here has said I don't know that it is going to work either, but I will still be out $800 (yes, that it what Jeep says it costs). It doesn't do it all the time, I can drive it for a week or month and it will be fine and other times I drive it for a day and it does it. Please help me and my mechanic before we lose our minds! I love my truck and I have 2 kids and we pull our boat, yada yada! HELP!

i also have a 1995 jeep grand cherokee 6cyl 4.0 i went and bought gas i put the cheap stuff in it that day because of high gas prices i had to go some place after that i was driving on a straight stretch of road and my car jerk it acted like it was gonna die on me but it didnt well it has done it several times afterwards. and it also i sometimes have to crank and crank to get it started i hit the gas pedal and then it will start but it doesnt do it very often and then one day i was coming home and my jeep jerked i thought oh no it died cause i put my foot on the gas pedal and it didnt do anything so i was going to pull off the road so i put my foot back on the pedal and it took the gas. its weird we put a new fuel filter in it just in case i got bad gas and i have used lucas this week i havent had any trouble out of it at all. i was told it could be the fuel pump starting to go bad. so if anyone can help me please please do. thanks a bunch.

I have a 1997 Jeep Cherokee Grand Laredo. I have also been having problems of stalling and stopping. I have checked the fuel pump changed the spark plugs and the cables and the distributor cap. I have supposedly had the injectors cleaned, and I am still having that problem. That the car will suddenly shut-off . It seems that gas is not getting to the engine. I want to know how to find out if the injectors are bad?

I had replaced the fuel pump and it still died. My other problem is that the check engine does not come up. I have taken it to the shop and they stated that they could not tell because the computer was not telling them the codes to look exactly what to look for. I really need to have this car fixed so I can get rid of it. It has just become a big headache. Please advice what to do? Thanks.

this thing goes dead while going down the road or after you have been driveing for awhile and stop for a light.We have replaced many parts just short of the brain and now we are brain dead ourselves. Please HELP Sometimes when this happens the dash lights will not come on for awhile and sometime the overhead lights will not go out and the pass doorlock can not be unlocked except by the switch on drivers side.PARTS that we have replaced in the last 2 weeks ing coil crank sensor cap and rotor button new wires plate on inside of dist sensor new idle control ? tempers are getting really bad over this vic again somebody please come up with something THE WIFE of owner of the JEEP