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-   -   Erratic idling (http://www.jeepgarage.org/f5/erratic-idling-17520.html)

mmain 01-16-2011 09:07 AM

Erratic idling
 
My 2005 GC 5.7 Ltd idles quite erratically, but not all the time. Is this symptomatic of a failing EGR valve, although I have no EVIC error codes that would suggest this, just from reading other threads?

lll2for3lll 01-16-2011 12:09 PM

Re: Erratic idling
 
You need a fuel system service. I have mine done like every 15,000 miles. But after the dealership did a bunch of software updates, it will probably be much longer than that before I need another fuel system service.

And don't go pouring junk in your gas tank. Take it and have it serviced. It's not very expensive.

kevin06vino 01-16-2011 03:21 PM

Quote:

Originally Posted by mmain (Post 335442)
My 2005 GC 5.7 Ltd idles quite erratically, but not all the time. Is this symptomatic of a failing EGR valve, although I have no EVIC error codes that would suggest this, just from reading other threads?

I had a similar situation with my 05. I replaced the EGR, plugs, PCV, tcm and PCM updates. I still have an occasional eratic idle. The 05's have plug wires so I will replace those in the spring for maintenance. I'm at 70k miles and a third owner so I can't verify previous maintenance.

Good luck


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kevin06vino 01-16-2011 03:30 PM

Btw I ran a bottle of Lucas fuel system treatment on my trip from Minneapolis to Saint Louis and saw a 3-4 mpg improvent on my evic along with a diablo 91 tune and dcx update on the ride down here.

I haven't entered my receipts in fuelly yet, but it's definitely improved. I do occasionally feel a shudder when I open the wife's door and the jeep is running.

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Scottina06 01-16-2011 03:34 PM

Re: Erratic idling
 
Quote:

Originally Posted by mmain (Post 335442)
My 2005 GC 5.7 Ltd idles quite erratically, but not all the time. Is this symptomatic of a failing EGR valve, although I have no EVIC error codes that would suggest this, just from reading other threads?

it will not necassarily throw a code if the egr is erratic.

lll2for3lll 01-16-2011 04:13 PM

Re: Erratic idling
 
Quote:

Originally Posted by kevin06vino (Post 335613)
I had a similar situation with my 05. I replaced the EGR, plugs, PCV, tcm and PCM updates. I still have an occasional eratic idle. The 05's have plug wires so I will replace those in the spring for maintenance. I'm at 70k miles and a third owner so I can't verify previous maintenance.

Good luck


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I'm telling you guys "fuel system service" will solve this. It's common. You see this guy had all this work done and it still idles rough. A fuel system service is needed every certain amount of milage for certain WK's. Look it up.

Please don't make a big problem out of a small problem. This most certainly is a small common problem.

lll2for3lll 01-16-2011 04:32 PM

Re: Erratic idling
 
http://gochemistry.com/fuelservices.htm

jeepgcoman 01-18-2011 12:50 PM

Re: Erratic idling
 
Scott's right, the EGR will not necessarily throw a code until it is grossly bad. If it is bad, your symptoms will be, noticeable surging at low speeds, erratic and sometimes stalling idle, and poor performance and fuel economy. You didn't indicate any maintenance history or mileage. There are other things that can give similar symptoms too, such as spark plugs (don't use platinums on a 5.7), MAP sensor, or even PCV valve, to name a few. On the 5.7's the trend on EGR valve failure seems to run in the 40-60K mile range. By the way, if you have a way to monitor the EGR function, a good working valve (on the 5.7) will run, at cruise, a commanded EGR setting of ~55-60% and error rates of positive or negative ~0-10%. They are continually changing too. A failed or failing valve will have the commanded and error %ages all over the place, sometimes unrealistically over positive/negative 100%.

kevin06vino 01-18-2011 09:03 PM

Re: Erratic idling
 
Quote:

Originally Posted by lll2for3lll (Post 335653)


According to WK Jeeps
http://wkjeeps.com/wk_maintenance.htm#TBODY

The throttle body can not be cleaned, so your fuel system treatment is essentially a "concentrated fuel conditioner to restore injector spray patterns and clean fuel rail, tank and lines" added to the tank.

After 1200 miles and a bottle of Lucas fuel system treatment, I haven't noticed a stumble. I'm still replacing the wires for maintenance, same as the other service I completed.

Best of luck and I am just sharing my experiences - it may not be the solution for you, but regular maintenance will make your Jeep happy and save you money in the long run.

4.whoa 01-19-2011 07:05 AM

Re: Erratic idling
 
Quote:

Originally Posted by kevin06vino (Post 337321)
According to WK Jeeps
http://wkjeeps.com/wk_maintenance.htm#TBODY

The throttle body can not be cleaned, so your fuel system treatment is essentially a "concentrated fuel conditioner to restore injector spray patterns and clean fuel rail, tank and lines" added to the tank.

After 1200 miles and a bottle of Lucas fuel system treatment, I haven't noticed a stumble. I'm still replacing the wires for maintenance, same as the other service I completed.

Best of luck and I am just sharing my experiences - it may not be the solution for you, but regular maintenance will make your Jeep happy and save you money in the long run.

I've seen this "don't clean the tb" before...but only after i did mine,at least twice. when I got it it was filthy, so I just cleaned it as with all the other cars i've had. I did spray it and wipe/scrub it with a paper towel to get the crud out of it, but aside from the throttle delay that is apparently normal on these hemi's (but drives me completly insane http://serve.mysmiley.net/mad/mad0229.gif ) i dont have any (noticable anyway) problems. Whats it supposed to do?:huh:

lll2for3lll 01-19-2011 10:40 AM

Re: Erratic idling
 
The fuel system I was referring was cleaning not adding chemicals to the tank.


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