paykoman86

I got Grand Cheeroke Laredo 2001, 4.0L with 112,000 miles on it JUST GOT IT !
It seems I'm struggling with the same problem---> Random misfire, !!
I tried most of the possible things already took it to three shops and still no idea
Dilership wants me to buy a new ECU also for a $1000 with labor but they said that thay dont guaranty it will stop the problem, found a shop that gived me price of $350 for a refurbished one with new programing etc
I know the car was previusly severely ovER HEATED
(sorry for my English, its my 2nd language) thanks for any help and advice

paykoman86

I feel your pain

paykoman86

what does steelership usualy suppoused to check when doing a diagnosis on older models ?
I'm not a mechanic myself.I think that if I exachnge somthing on a car and it does not help/fix the problem I supposed to be able to return the damn thing (especially something like a computer) "thats not the way it works sir" WTF ?
should I go for the reprogramed used computer for 1/3 of a price ?
b/c Im reading posts that people did it and it did not help at all.
and my main question is why sometimes it runs like a champ even for couple hours but mostly misfire is so severe that its not driveable?

charginchuck

I had the same issue with my 2000 xj. Have your injectors cleaned. If you google it you can find a do it yourself injector cleaner. I made mine with a 5cc syringe, a 12v power supply, a momentary push button switch and a can of carb cleaner. Have not had a problem since. I did find some particulate matter in my fuel rail and when I cleaned the injectors you could see the difference in the spray pattern. If you drive on alot of dirty or dusty roads you'll definitely benefit from checking them out anyway. After everything else you've replaced this would be the next step. After that check your O2 sensors (if yours is CA emissions you have 4 of them ) then yours cats. Good luck!!

94.2door.xj

try the Chrysler injector swap mine is doin the same thing under a load im gonna clean out the gas tank and do the newer injector swap
timing, compression, spark and fuel it should run lol good luck

az4wheeler

I too have the 01, used the heat shield around the #3 and #4 inj. also made sure plugs were new and used correct plugs. everyone thinks hey! i'll go and use platinum (i did) and you will be sorry, go and use the "factory" autolites and gap them to .45 you should be in good shape. i have not had any codes since this and its been 6 mo.

paykoman86

so you tell me I should get oryginal sparkplugs check the wires myself, and clean the injectors ? is it easy to do ? or should I leave it to steelership ?
shouldn't they check that injectors are working doing the diagnosis?
I hate this damn thing :/:/:/

EMAXX620

injectors arent bad to do, you dont NEED to take them out to clean, just add some seafoam to your gas tank when your a bit low. says to add 1/3 to a full tank but you can add half can or so to half tank of gas. for the plugs, just use NGK, autolite, or champion.

if you really want to take them out to clean them, your going to need to build some kind of rig to flush some carb cleaner or similar thru them while opening and closing the injector with 9-12v. flush them forwards and backwards

AstroXJ

Well i'ts been over six months since I started this thread. I haven't had much time or money to work on the Jeep. Recently I tried a new o2 sensor only to find out the 2001 models have FOUR o2 sensors (2 uptake 2 downtake). I could only afford one sensor so tested it on one intake o2 sensors and still misfired. The os power cord was too short to reach the other uptake port so I took it back to parts store. I ordered a Crank Position Sensor (CPS) on eBay to try next. Since these distributless motors depend on this sensor, its would make sense to be culprit. Anyone have random misfires due the CPS sensor? I would think the computer would report the code for a CPS failure but I don't trust computers.

paykoman86

How can I tell that they're working OK /.? the injectors /.?

84zmyfavorite

Theres no factory aluminum head on any year 4.0!

DM_MKV

I know you already said vacuum but have you checked the gasket between the intake mani and head. Mine was not showing to be leaking when I checked with starter fluid. Then finally said f it I am going to clean and replace it and now it doesn't misfire.

Just my .02

EMAXX620

you can test the ohms across them i believe, but a more simple way to just test if they are working at all is to put a 9v across the connector and see if it clicks. easier to put a momentary on push button switch in it so you can click it a few times to see if its clicking.

heres my post on how i cleaned my new ones
https://www.cherokeeforum.com/f2/how...81/#post601825

paykoman86

I had a little argue with the steelership today & had to pay $200
for a diagnosis + Fuel pressure TEST, Fuel DRAIN & $20 worth of new fuel and another DRB TEST (no misfire codes )
Result--> Needs NEW PCM ,ONLY NEW NO GUARANTY or possibility of returning if doesnt help $1000
they said that they will not do any more testing b/c they dont need to :O
(I was hoping for a engine compression check & injector noid test)
Found a place that says that they will check my ECU-PCM-CPU for $40
reprogram it for $90 and if its bad a used reprogramed for $250
SADLY Im not able to any work on the car myself b/c of where I live
I know previous owner verry well, he left me the car after getting 4th DUI
befor leaving he told me that there was a lot of work done on a car like
1 of coil packs is new, spark plugs, wires, new exhaused, shocks, TMC reseted, ETC
but I dont really know what exaclly was accually DONE and checked !!
no receipts, no phone numbers
so I cant really relay on what he said :/
what do you think ? what should I do ?

01XJack

I have the exact same jeep with the exact same problem after doing the exact same diagnosis fixers on it!!!

and still having the #5 code (maybe heat soak) I don't know!!

Did you end up finding the problem?