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Idle at 500 RPMS and shakes while stopped

51K views 21 replies 12 participants last post by  DCFD522 
#1 ·
I have a 2006 WK limited with the 4.7V8. It has 88k on it and I purchased it about two months ago. Not sure of the service history, but the car runs good other than the idling. I have never owned a jeep and at stop lights or in park the car idles at 500 RPM'S and it shakes/shutters-is this normal?

Has anyone experienced this and if so what have you done to fix it? I've searched this forum, but I haven't found anything regarding my specific issue.

To date:

I installed the OEM spark plugs (two weeks ago) and it didn't solve the shakes/shuttering.

I brought it to a Jeep dealer last week and they told me it is idling normally, but I couldn't imagine that rough idling would be normal.

Any info. would be great!

Thanks Ray
 
#2 ·
Clean the throttle body and PCM flash. Two simple solution that will for sure solve your problem.

And maybe replace the PCV and EGR valve.
 
#3 · (Edited)
I am not going to lie... the 4.7 is an engine that I have found pretty commonly to have a kind of unbalanced "shake" or "shimmy" to it. it feels like a slight misfire. Some are much worse than others. I notice it kinda come and go on mine.

At work I replaced intake valves and keepers due to a coldsoaked misfire. This one in peticular had a very noticable shake to it when I pulled it in and I kinda figured that would be resolved with the new intake valves... it did not at all, it shook very much even after, but no more cold misfires.

BTW, my PCM is up to date and so was the other one, and my throttle body was removed and cleaned thoroughly, IAC removed and all when I put the engine back together 6 months ago.

Your idle speed is normal.

your issue may be a failing (sticking) egr valve, on the one previously mentioned that was something I checked and it was not. you can check it by loosening the bolts to the egr tube, remove it from the intake manifold and plug the hole, if it clears up you know its allowing gasses to flow.
 
#8 ·
Everyone has good input/suggestions, but just be aware that these engines are completely electronically controlled and utilize numerous sensor feeds to the PCM. The PCM then sets engine parameters according to these inputs. Without having a way of checking and verifying the accuracy of the various sensor inputs it'll probably difficult to hit on the cause, unless someone has had the exact problem along with the solution that fixed it. IMO, that's why these forums are so neat. After reading some of the problems and solutions, I think many of us could go to the dealer/mechanic and tell them what's wrong and how to fix a given problem.

Anyway, off the soapbox. I don't believe your idle speed should be that slow under any normal condition. Rob fixed his with the SC tuner (a good choice, IMO), but I can't believe the normal curb idle would be so slow that causes the loping and shaking. Has anyone looked up what it should be? I know my WK 5.7's stock idle is ~625 RPM and my LX 5.7's stock idle is ~650 RPM. I've done like Rob and bumped them both up ~50 RPM, just because it's my preference.
 
#9 ·
My jeep is doint the same thing I replaced the tps and iac as well as the map sensor and on monday i replaced the plugs with stock champs and gapped at.40 nothing changed I than seafoamed and nothing changed it will idle at about 500 when before it would be at 650, im thinking egr valve?
 
#10 ·
I am having the same rough idle issue as you describe. Mine only does it intermittently, but at times it is rather rough. I have had the PCV valve, sparkplugs and an induction cleaning and nothing has helped eliminate the problem. Although the engine does run alot better, the terrible idle is still a nuisance to me. On Friday next week I will have my EGR valve replaced and I will post the results. I am also trying to diminish an audible tick when accelerating, so hopefully I can report some hopeful news back to you by next weekend.
 
#11 · (Edited)
I just had the EGR valve replaced and I can say that nearly all the rough idle is now gone. For $55 for the EGR valve through Rockauto plus $37.50 for the install, the issue appears to be resolved. I have not yet had a chance to measure any improvement in gas mileage, but time will show. Hope this helps you in deciding whether replacing the EGR valve may be an option in your situation. Good luck!
 
#13 ·
Not sure if you're still having this issue. I had the same problem and I ended up having my IAC cleaned out and that stopped the problem for me and it improved my gas mileage alot. I noticed that it gave me more power as well and didn't act sluggish like it did before.

Hope this helps!
 
#19 ·
HOLY PLACEBO BATMAN!

it is physically, electronically, theoretically, and operationally impossible for the IAC to do everything you have stated. The IAC does nothing but idle control, if it sticks open or is just dirty it wont have any effect on the driving operation of the vehicle. Because Chrysler uses speed density even air past a leaking IAC is used in the fuel calculation. It just cannot do... anything you stated, OTHER than possibly smoothing out an idle.

This is really common, mine does it here and there.
 
#15 ·
I replaced Manifold pressure sensor MAP, Throttle position sensor TPS, Idle air control valve IAC, PCV Valve, Spark plugs and the Air filter on my 2006 GC limited with the 4.7L engine. with no improvment of my bumpy idle. I will now try the EGR valve to see if that works, thanks for the tip. tony
 
#22 ·
Bump for an old thread.
07 3.7 QT1 w/drive-by-wire TB.

Anyone ever get their idle up from 500? Mine will idle there only when its warm.

So far I've:

Replaced TB (went from a 3.7 to a 4.7, easy mod)
Replaced Injectors (3 were low flow on test)
Replaced EGR
Replaced PCV
Replaced 4 O2 sensors
Had charging system checked, voltages were all normal.
Had compression checked, all were normal.
Had several loose cam valve covers and one with sheared bolts (was causing a ticking noise at operating temperature...tightened to specified torque and replaced bolts as needed(fixed))

Prior to purchasing, Ignition Coils and Spark Plugs were done 10k miles ago.
PCM was updated around 10k miles ago.
New Radiator 10k miles ago.

Overall my mileage has gone up 4-5mpg, into the mid teens city driving (14-16mpg, 20+highway). When my HVAC kicks on my idle searches between 480-650. When warm without the HVAC on it is steady at 500.

On the to-do list, crankshaft, camshaft, and map sensors. Jeep is running amazing now other than the lower idle and the wacky HVAC.

Any thoughts? Have a similar thread I hijacked on no power, but no one seems to want to chime in. Also have one on JeepForums..seems like a common problem, especially the random surging.
 
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