2010 Jeep Wrangler Engine Loping

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#1
2010 Wrangler, 3.8L, automatic.
When the engine is cold in the morning the engine lopes. (When the jeep is in Park or Neutral) I can push the peddle to the floor but the RPMs don't go above about 1,000. The loping stops when the engine warms up. It will drive properly but the loping stops me from warming up the jeep quickly.
Any ideas?
 

nickb2

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#2
Is check engine light on at this time? Is your cruise switch inoperative?

There is a TSB for this. Idle buffeting and cruise switch inoperative. Requires a reflash.
 

nickb2

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#3
Do you have access to a scan tool? If not, cycle key on, off, on, off, on. The odometer should give you a code instead of mileage. Something like P050D

Check my attachment for tips for cold start rough idle.
 

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#4
No check engine light or anything. Everything is working as normal.
How would I find the TSB you mentioned?

Thank you.

Steve
 
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#5
I don't have a scan tool. But I will try the ignition thing you mentioned tomorrow morning (or when the rain stops).
Thank you.

Steve
 

nickb2

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#9
It could be several things since it's not illuminated the check engine light.


However, the PCM may have one or several pending codes that haven't tripped the light. These are two trip cycle codes which will either remove themselves once problem is corrected or code on the next drive cycle if still present causing a hard code which will trigger check engine light.

You may have a vacuum leak which corrects itself as temp rises. It could be a faulty ECT (coolant) sensor.

What is your level of mechanical and technical understanding of basic electronics and the injection engine?

This is a 2010 Wrangler with many modules on board. A basic knowledge of OBD2 is needed. Do you know OBD2 systems?
 

nickb2

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#12
A scan tool shines here for intermittents or as you are describing, cold problems that disappear (or so they seem) when hot.

A scan tool will tell you if you have pending codes waiting. When you idle problems goes away, that discrepancy is stored and if still present even when hot, it will trigger the check light.

Often, a cold condition could also be that the PCM is correcting and smoothing out idle because long term adaptive fuel trim is now the base of fuel trim.

It would be awesome if you could get a vacuum gauge on that engine a start up cold and see what is going on. Also noting fuel pressure and getting ECT temps. The ect temp cannot reliably be gotten unless you have a scan tool or at the very least a heat probe at ECT sensor and observe rise with instrument panel giage, again, not ideal. Best to see what PCM sees.

Can you smell a rich exhaust when it is doing so? Would be an indication it is adding fuel and maybe not vacuum leak. All these scenarios are not ideal. These OBD2 systems have gotten way more sophisticated in the past few years.

A cheap scan tool interface and a laptop go a long way. A cheap elm interface can be gotten for 15-20$ on amazon or e-bay. Check it out. They are called ELM OBD2 scan tool. They come with a cd to help get that usefull data on a laptop or android phone with torque pro.

Here are some links

http://www.ebay.com/itm/ELM327-WiFi-OBD2-Car-Diagnostics-Scanner-Code-Reader-for-iPhone-iOS-AND-Android/331175483846?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D27710%26meid%3D2f93598c55f149668a062bfedf88449d%26pid%3D100005%26prg%3D11385%26rk%3D3%26rkt%3D6%26mehot%3Dpp%26sd%3D131359960106&rt=nc

https://play.google.com/store/apps/details?id=org.prowl.torque&hl=en this will work with the ELM 327.
 

nickb2

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#13
That TSB I was talking about is useless if your cruise switch works. I won't waste time downloading it until you check all the rest, such as codes and all the above and cruise switch.

@ what temp do you see the symptom go away? Do you hear a whistling or wooshing sound in engine bay when it is doing it?

I imagine this is no longer under warranty?