Vibration at idle in drive?

[george0029]

I've had this slight problem ever since I bought the KJ.
When I'm at a red light, and I let off the brakes enough for the jeep to start rolling, the whole thing shakes.
I'm pretty sure this is not normal, and I'd like to know what is causing it.
The shaking is not severe, but feels like something is wrong. I've heard engine mounts sometimes cause this?
It all goes away once I touch the gas at all.
:shrug:

Any thoughts? Much appreciated!

 

[LibertyTC]

What is the rpm when it does this? Any check engine light?
When was your brakes last inspected?

 

[badkittystt]

My car that I don't drive anymore (2000 Toyota Echo) does that and the boy says it's because of the engine mounts. Apparently it's not a hard fix but now that I have my jeep I just don't care. I noticed that once that started shaking other stuff went a little loose, mostly my back speakers.

 

[RenegadeJay]

My car vibrates enough to see my empty passenger seat shake. When I take my foot off the brake and barely idle forward it seems more of a jerk-jerk movement than vibration. Never had it looked at as I too thought it was just a worn mount. I prolly should but you know how mechanics can never "duplicate" the issue.

 

[tjkj2002]

Checking the motor mounts takes 20 seconds,look for cracks and such.

But......................

My KJ has that slight vib when in gear and stopped,the antenna shakes, since mile 3,actually a little worse now since I stiffened up the unibody(and yes brand new OEM motor mounts,plugs,and coils).

 

[george0029]

My car vibrates enough to see my empty passenger seat shake. When I take my foot off the brake and barely idle forward it seems more of a jerk-jerk movement than vibration. Never had it looked at as I too thought it was just a worn mount. I prolly should but you know how mechanics can never "duplicate" the issue.

yeah that's exactly it!

as for the other questions, it is around idle rpm so 600 or so I believe?
I'll leave my OBD plugged in one day and get an exact number.
No check engine light.
and the brakes I just replaced the front rotors and front and rear pads over the summer so unless it's the back rotor I think they're okay.

like RenegadeJay said, it is more of a jerking movement than a vibration, and goes away with any touch of the gas.

 

[WesChapman]

Mine has always done this as well. 107k miles now and it's no worse than it was at 14k miles.

 

[J-Thompson]

IMO this is another down fall of the 42rle
sounds like if you let off the brake but dont touch the gas it vibrates?
just like it "shudders" when reversing up hill?

if it is simply engine vibe then motor mounts but it would vibrate while stopped
and the worst case of this is the Ford Escape with the 4 cyl. ,we have 1 at work
I drove it twice the second time was to the dealer
they said it is normal for "all 4 cyl. cars to do this" "really? not the 1 I drive"

 

[RenegadeJay]

"shudders".... much better way to describe it! :waytogo:

 

[Bullett55]

Trans clutch shudder, not that unusual for the 42RLE. Usually particularly noticable backing up even a slight grade. IMO...,
if it's not shuddering badly I'd just let it be. If the Dlr gets into it they're gonna also re-flash (update) your module (depending on the vehicle year). And sadly once they do this re-flash, you will lose the ability (that you used to have) to 'feather' in and out of lock up above ~45-50mph, which was really nice for light load situations. Ask me how I know - grrrrrr.