TREX212426

When im at a stop light and I have the foot on the break I feel a light vibration. My box only has 4,600 miles and a sport exhust. I was wondering if this is normal or do i need to worry :?: :twisted:

elwood58

Others have posted about this as well. Seems to be more pronounced with A/C On after running for a while. Does not sound like anything to worry about.

By the way, those that have installed the grounding kit claim to have minimized this issue.

FeeLTHeBuRN

happens to mine and i just hit 5000 so I would assume that it is normal

jct

mine vibrates way too much, oh wait thats just my cd player with max vol.

mgithens

mine is smooth as silk... oh wait... I got a stick... that is just an automatic problem...

hotbox05

maybe it's just me but when you hold in the clutch and rev the motor is there a vibration in the clutch pedal? ive never had fwd b4 so maybe it's that i unno. .. never on my supra , bug , or bmw , or datsun so.......... i unno tell me if i should be worried . not like horrific or nothin but more than in any other car i've driven.

KevinxB

My stick does the same thing they are describing. I don't know what the cause is.

UnFocused

Its because w/ an automatic in "drive" or "d", the car wants to go by itself. when you let off the brake it will roll on its own untill you give it more gas. the vibration you feel is from the transmission itself. If you put in "n" for neutral- it will subside.

Every automatic Ive ever driven does this!

My old Focus did it horribly!!

chucksu

Yes this is what it is. It has to do with the torque converter trying to engage & disengae so it creats some drag on the engine. Some of my older autos it was hard saying if it was the engine vibration (from being rwd v8 cars) or if it was the tranny.

Kool_B

Funny the same thing happened to me yesterday as I was leaving my favorite Mexican Restaurant. I was sitting at a light and felt a strange vibration in the seat area and.... Oh Geez... It was me I farted.

MRGTHUNT

Mines did the same but I took it back to the dealer. Turns out that my intake was too big, and there was something about how my intake wasnt all the way connected. The vibration was from the air not flowing right (thats what I was told). So he said he cut some inches off of it and it worked. But now my right foglight shakes even though I cant feel the vibration. Now what to do?

X_Boxer

Agreed. I don't yet have my scion so I will add a general fact: it is low frequency torque reaction. Yes, the auto is always feeding engine pulsations if we are in gear, stopped, foot on brake. Four cylinder power pulses occur every half turn of the crank. Uneven, shove, slow, shove, slow. If the "vibration' ceases when the auto is put into neutral then diagnosis confirmed. No fault, just a timeless truth: more cylinders are more smooth because power pulses are more frequent and not so indidually like kicks. Witness the extremes in luxury cars past and present: ten cylinders, Even 16! Tiny cyls, but many of 'em. Primitive monster race cars of a hundred years ago had only four cylinders -at most-. Jugs so large as to practically swallow a modern rice burner engine! Fire breathing monsters, up to nearly TWO liters per cylinder. SOME major torque reaction vibration there, you bet! Our great great granddaddies would laugh at our modern description of a worrisome "vibration". Everything is relative to time and expectation. Four cylinders are great, economical, durable, cheap but not the acme of running smoothness at idle and low end full power application. Pardon my ramble, just data for the curious minds out here. I used to drive a Model T every day- hand crank it, too! Talk about torque vibration- at critical speed a model t shakes like a wet dog. Personality plus, those old cars.

mgithens

you are close, but you are leaving out some major facts... the reason that an older larger displacement engine runs "smoother" is generally due to the lower compression and much higher mass of the flywheel...

an automatic transmission contains a torque convertor, this device serves two beneficial purposes, #1 it multiplies the torque the engine is putting out... it can be like 4X more power because of how the device works, but this is only at launch... #2 it provides a place for there to be a "disconnect" between the engine (which must keep spinning at the red light) and the transmission/wheels (which must come to rest)... the fact that the car keeps rolling when you let off the break is because the torque convertor doesn't "release" like the clutch does on a manual...

TREX212426

Thanks to all of you for your input and suggestions. I might just take it in just to be on the safe side. :twisted:

KevinxB

So why would a stick do it, then? There is no torque converter. I notice a vibration in the clutch pedal whenever I am at a stop and have the A/C on, but never with it off. Is that normal? No other 5 spd vehicle I have driven did that.

Cybergypsy

I did notice this on a test drive of a XB....the salesman said it was normal...

boilerman

In the case of old timey automobiles when the AC compressor was engaged at idle I seem to recall that the idle speed seemed to drop and the engine seemed rough. A check of tach with compressor off and on at idle might indicate a drop of RPM which could seem like rough idle. With the new magic electronic controls the idle RPM might be adjusted to normal with compressor on at idle.

mgithens

because it is a mechanical system, the pedal is the only place you are coming into direct "hard" physical contact with any part of the engine... your hands on the steering wheel can feel the compressor (but not as well as the foot), but your but in the padded seat can't...

the condensor on your air conditioner on your house (the outside part) makes all kind of noise, and only a small portion of the noise you hear is from the fan blades - the majority is from the motor turning those blades - I don't see anyone running out to fix that vibration...

TREX212426

Hey i Feel it on the seat as well is that a problem? :twisted:

its_ikon

i had the same thing happen today