08 Jeep Wrangler short rough idle then normal

[Colorado4]

08 Jeep Wrangler JKU, when running has short rough idle about 1/2 a second and then normal idle returns. Cycles like this.

Any ideas? Besides obvious its a jeep.

 

[WJCO]

08 Jeep Wrangler JKU, when running has short rough idle about 1/2 a second and then normal idle returns. Cycles like this.

Any ideas? Besides obvious its a jeep.

No codes or engine light?

 

[Colorado4]

No codes or engine light. After closer inspection saw spark plug wire arcing. Split a wire when replacing the exhaust manifold. All is good now.

 

[DirtHeadDavis]

No codes or engine light. After closer inspection saw spark plug wire arcing. Split a wire when replacing the exhaust manifold. All is good now.

So what you're saying is... it's a Jeep? Lol, an easy fix.

 

[Colorado4]

So what you're saying is... it's a Jeep? Lol, an easy fix.

Slowly learning to have patience with it for sure! Lol!

 

[wayoflife]

08 is a Jeep with a 3.8L that's been around for a long time. Safe to assume you've done normal maintenance on it like change the spark plugs, etc?

 

[Colorado4]

Yes sir. 50k miles on it. It was my uncles and it sat in his garage for years.

Changed diffs, trans, belts, tensioner pully, spark plugs, put synthetic fluid in everything possible. Of course the PCV valve, range sensor and exhaust manifolds.

Turns out when I replaced the manifolds this week I messed up a spark plug wire, which was causing the idle issue.

This forum and your videos have been very helpful.

 

[Slimebones]

I wouldn't be surprised if this issue comes up again, even though you found an arcing spark plug wire. I have an '07 with the 3.8 and have had this issue going on 7 years now. Very sporadic, no pattern. Even seems like the engine actually dies for a split second when at idle. Can not find the cause. Seems like I recall this issue coming up on this forum a few years back. No obvious solution tho.