Vibrations at idle

jamesrw30

Active Member
Ever since I picked up my JK it's had vibrations when at idle or really low speeds. Once up to speed it seems fine. I feel it all over like in the seat and feet and all. Any ideas what this is? The RPMs seem to be stable while idling so I don't think it's a low idle but I'm also not a mechanic and most everyone here has way more knowledge than I do.
 

jeeeep

Hooked
does it vibrate in neutral?

I'd check the transmission and motor mounts, make sure they are at proper torque; also look for signs where there might be movement like shiny spots around the mount or where the transmission may be slightly moving.

depending on mileage, may consider checking the plugs / coils but it's a PIA
 

TrailHunter

Hooked
Or something creating a path between engine and the frame. Like something touching when it should not be.
This... I had a harmonic vibration on my 05 GMC Diesel... Sounded like it was coming through the brake pedal and only happened at Idle in park or in gear.. Drove me F'n nuts for like a year or something... Finally figured out a brake line was resting against the master cylinder... Bent it away and the vibration was gone. It felt like I won the lottery.
 

WJCO

Meme King
Next time it's vibrating at idle, put it in neutral and put it in reverse just to see if vibration goes away. I'm thinking motor mounts like others have suggested.
 

AgBass01

Caught the Bug
My 2012 had a resonating vibration because the exhaust system wasn't secured correctly.
My '12 did the same thing after installing an exhaust spacer. This caused the exhaust pipe to be too close to the transmission skid, I just added 1 extra washer on the skid to space it from the exhaust pipe and it went away. Of course now that I have proper lift, control arms and drive shafts I should probably take the exhaust spacer out and remove that extra washer/shim but who wants to pull exhaust apart.
 

jamesrw30

Active Member
Still present in neutral and park but definitely worse in drive and reverse. Checked motor mount bolts where the frame mounts attach to the engine mounts. They seemed tight. Looked around under the hood. Didn't see anything that seemed out of place. Drive shaft didn't seem to have any play and it looked like weights looked to still be in there. Plus there was standing water in passenger floor board after a huge storm the other day. So yay for that
 

jamesrw30

Active Member
I do not. Did find water coming in through the bottom of the door. So I guess the door seal is shot.
 

jeeeep

Hooked
I would loosen the engine, transmission and transfer case mount bolts, see if anything moves into position then tighten back to torque spec.

I wouldn't rely on the bolts feeling tight, something may be out of position.
 

TrailHunter

Hooked
Have you started the jeep... let it idle, recreating the vibration and crawled all around it with a flashlight? Touching shit, feeling for vibrations etc?
 
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