Rough idle
Thread Starter
JK Freak
Joined: May 2011
Posts: 741
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From: Watertown, NY
Rough idle
I have a 11' jk with 13k miles and I've been having an issue with rough idle.
At red lights the tachometer drops to about 500 rpm and the engine almost dies but hasn't yet. If I give it a little gas it has a temporary fix. Any thoughts?
At red lights the tachometer drops to about 500 rpm and the engine almost dies but hasn't yet. If I give it a little gas it has a temporary fix. Any thoughts?
JK Junkie
Joined: Oct 2007
Posts: 2,565
Likes: 0
From: HAWAII
Aside from bad gas it could be a dirty TB...I know 13k miles shouldn't have that problem, but it doesn't hurt to check....see the thread below....
Let me get right to this. If you are experiencing rough idle and/or sluggish throttle response, your throttle body is more than likely dirty. I plan to clean my throttle body every time I change the air filter, so every 10 to 12k miles. I bought my 2007 Sahara with just over 43k and I don't think it had ever been cleaned. Anyway...here we go.
Disconnect your positive battery post. Better safe than sorry.
Front view of Throttle body prior to removal and cleaning.
Slide red retaining clip on air temp sensor and unplug.
Using a flatblade screwdriver, loosen the clamps and remove the intake duct. You can now clearly see the Throttle Body has some oil film and buildup.
Unplug the throttle body control harness. Simply pinch and unplug.
Now remove the 4 torx bolts holding the throttle body and remove throttle body.
As you can see, my throttle body was dirty on the exterior side of the throttle blade.
The interior side of the throttle blade shows why the idle was rough and sluggish.
Using STP Throttle Body cleaner and a blue shop towel, clean the throttle blade and tube. Some people swear by seafoam so whatever works for you.
Simple put everything back together in reverse order of how you took it apart. As for the torque specs on the throttle body bolts, 5.5 ft.lbs or 65 in.lbs is all it takes. Like with all tightening to a specified torque, tighten bolts in a cross pattern. I used the same throttle body cleaner to rinse out the intake duct tube. I also used a shop towel to clean what I could reach of the inner intake.
That's it. It took a few minutes for the computer to smooth the idle out, but it was smooth as could be after a short 5 minute drive. Throttle response was smooth and responsive (as responsive as these jeeps get). Some dealerships have been know to charge up to $135.00
for this simple job that took me less than 30 minutes to do. My total cost was $4.50 for the can of TB Cleaner and roll of shop towels. Simple and cheap.
Disconnect your positive battery post. Better safe than sorry.
Front view of Throttle body prior to removal and cleaning.
Slide red retaining clip on air temp sensor and unplug.
Using a flatblade screwdriver, loosen the clamps and remove the intake duct. You can now clearly see the Throttle Body has some oil film and buildup.
Unplug the throttle body control harness. Simply pinch and unplug.
Now remove the 4 torx bolts holding the throttle body and remove throttle body.
As you can see, my throttle body was dirty on the exterior side of the throttle blade.
The interior side of the throttle blade shows why the idle was rough and sluggish.
Using STP Throttle Body cleaner and a blue shop towel, clean the throttle blade and tube. Some people swear by seafoam so whatever works for you.
Simple put everything back together in reverse order of how you took it apart. As for the torque specs on the throttle body bolts, 5.5 ft.lbs or 65 in.lbs is all it takes. Like with all tightening to a specified torque, tighten bolts in a cross pattern. I used the same throttle body cleaner to rinse out the intake duct tube. I also used a shop towel to clean what I could reach of the inner intake.
That's it. It took a few minutes for the computer to smooth the idle out, but it was smooth as could be after a short 5 minute drive. Throttle response was smooth and responsive (as responsive as these jeeps get). Some dealerships have been know to charge up to $135.00
for this simple job that took me less than 30 minutes to do. My total cost was $4.50 for the can of TB Cleaner and roll of shop towels. Simple and cheap.