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2005 Grand Cherokee idles rough and stalls when im at red or stop light.Help anyone??

42K views 30 replies 13 participants last post by  kuker 
#1 ·
i have a 2005 grand cherokee laredo 4x4 4.7 liter v8 with 88,000 miles and has stalled before when id come to a stop but was every now and then , but now its doing it all the time and its getting really frustrating real fast. ive read that its a common problem but nobody seems to know a fix? what is one to do , i used to love my jeep before it started doing this, help please :confused::confused::confused:
 
#6 ·
How much should these treatments run? Reason I ask is my local garage wants to replace all 16 plugs in my Hemi and do a fuel service to the tune of about $400. I won't disagree that my WK needs it, but that sounds high to do maintenance every 15-30k.

I am not mechanically inclined so DIY is out of the question for me.
 
#20 ·
If you can plug in a lamp and have mastered "left loosey, righty tighty" you can change your own plugs. It may take a couple hours the first time, but it really doesn't require any special knowledge or any tools beyond basic hand tools.

You need a basic socket set, simple bar style torque wrench, spark plug socket, spark plug gapper, a 4" extension, a 6" extension, a wobble joint, and a long extension, 10", 12" whatever. A stubby 10mm wrench will also make life easier.

Pull the spark plug boot off by hand. Put the spark plug socket on the short extension (either 4 or 6, depending on how much room at that cylinder) and turn left until the plug comes out. Gapping a plug is as simple as bending the little wire until the correct size feeler goes into the gap. Gap the plug, put it in the hole, turn until it feels tight, then put the torque wrench on it and push until the little needle points to the 14 on the ft/lb side. Use the 10 mm wrench and 10mm socket, remove the coil pack next to the spark plug boot, (2 bolts, one top and one bottom) lift it up, do the same thing under there to remove and replace the spark plug. Put the plug boot and coil pack back on, move to next cylinder.

The only remotely challenging thing is getting to the front 2 cylinders on the driver's side, and that's where the really short extension and wobble joint come in. Drop the short extension and socket in the hole, plug in the wobble and a long extension, and you're turning the wrench way above the tight mess.

You'll save yourself almost $300 and it really is that simple.
 
#7 ·
ive seen a number of things that people claim to be the problem. egr, throttle position sensor, etc. i just put a bottle of seafoam in my gas tank and i changed my plugs about 2 months ago. my idle has been rough since i bought it and the seafoam may have helped alittle. i dont feel that a fuel system service will fix the problem. i am also not saying that it wont.
 
#10 ·
Look at the simple solution first. Get a fuel system service. Mine starts to idle rough every 15,000 to 25,000 miles or so (starts to idle even rougher if I drive even longer to the point where it sounds like it will shut off) and the fuel system service gets it right everytime.
 
#14 ·
I wouldn't do seafoam in my Hemi. Fuel service every 15-20k seems more like masking a problem rather than actually fixing it. I have 88k on my Hemi and have yet to do any of the above. Still runs great.
 
#17 ·
I've had issues with seafoam loostening up deposits that were holding things together (ie gaskets) but if you use in the correct doage (1/2 can in gas, 1/4-1/8 can in pcv, 1/4 can in oil prior to change) it should never foul cats or o2 sensors
 
#26 ·
Problem solved. It was short on transmission fluid, about a quart to be exact and told torque coverter might of been sticking, but added the atf+4 and its back to normal, but runs smoother than before w the fuel system cleaning, it needed it but the reason for it dying was the trans being so low.... nuts, just glad its okay now, i love my jeep.
 
#28 ·
Hey everyone, i have the same problem.. it started just one morning some days ago. The day before it was fine, now it shuts off at almost every stop. Sometimes i can see the computer trying to keep the idle because the tach oscillates between 200-1000 rpm.
My 2005 WK has 188 k miles. I haven't changed the plugs or serviced the fuel system.. oops!
I'll keep you posted.
 
#30 ·
I posted my results in another thread, but long story short, it was my IAC and possibly TPS that were bad.
I changed both WITHOUT disconnecting battery and idle was fine, but the Jeep would hesitate from a stop, and occasionally die as I would come to a red light.
500 miles later I disconnected the battery, waited a minute, reconnected and now it runs fine. I can tell the tranny needs service but that's a different issue.
 
#31 ·
Biggest thing on hemis on tune up time is take throttle body off to clean it, doesn't look bad from the front. The back will make you sick. Took me about 30 min of scrubbing with an old tooth brush, but after had loads better response. Yes, hemis burn through plugs, but they fire x2 per rev of any other engine. Bonus, hemi HATE fancy spark plugs, so unless you have serious ignition mods, don't waste your money. About half or better run worse with new platinums etc. then old copper champs. As far as struggling idle, can be a lot of things, EGR issues, plugged CATs, sticky throttle body, fuel filter, crap in fuel system, and so on. How many know that a minimum octane of 89 is required for a hemi.

For those not mechanically inclined, find a shop where you get to talk to the guy doing the work, and he better be a mopar fan. If not, bring some personal lube. IMO hemi is the absolute best contemporary engine there is. They do take maintenance, but for the most part, it's easy, cheap, and if you need a step by step it's right here or youtube if you want video. Sorry for the novel, but the short version is "maintaince is the first troubleshooting step"
 
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