car shakes when sitting still

[blueindian]

we have a 2001 nissan altima with ~120k on the odometer. when i pull up to a stoplight the car shakes while i'm sitting still. it i put it in neutral, it's perfectly still. but as long as it's in gear the whole front end shakes.

what gives? it's an automatic, btw.

[Bires]

...it's an automatic, btw.

That's your problem. Nearly all older autos do this. It needs service. You have some fluids that need changing (at the least) and possibly new motor mounts and bushings to replace.

[mechmike0034]

A dirty, gummed-up throttle body can cause low idle airflow and a resulting rough idle. Bires is correct on worn motor mounts. Most vehicles have rubber motor/transmission mounts that wear over time, and this can "amplify" a rough idle.

Vaccum leaks can also cause a rough idle. Actually, many things can, but the two most common causes are the two I mentioned.

[civicdidex]

is this amplified when your AC is on?

[mechmike0034]

is this amplified when your AC is on?

Sure - A/C = extra load on the engine at idle. Most modern computer-controlled vehicles have a way for the engine control computer to slightly increase idle speed to compensate for this load. If the throttle body or idle control device is gummed up this strategy may not work.

[MrGreg]

Check your rotator splint

[BigJon]

Have you taken the hookers out of the trunk? They could be rolling around trying to escape and causing the vibrations.

[ufcrusher]

Check your rotator splint

No it cant be the rotator splint...it has to be that Turbo-nator (TM) that he installed for better gas mileage. Hell, it tripled his gas mileage and gave him a huge power boost!

[johnnymk]

Check your rotator splint

also check your muffler bearings :)

[bachviet]

Engine mount