Vibration - Accelerator Pedal
><< 2. Recently I have noticed under heavy acceleration in 1st, 2nd, or 3rd
> gear, a vibration in the accelerator pedal. I don't know whether it has
> been there all along, or that since I've picked up on it I'm more sensitive
> to it. It is curious that it only occurs with the clutch engaged, as I can
> be cruising and disengage the clutch, sustain the same engine RPM, and not
> feel it. >>
>I too have a slight vibration in the accelerator pedal, more noticeable the
>harder I accelerate (mine is an 87 automatic). You can't feel the vibe with
>the clutch disengaged because the engine is no longer under load - you did say
>it only occurs under heavy acceleration. More engine torque means more engine
>vibration, and if the motor mounts aren't doing their job very well, it
>probably gets fed into the gas pedal - I presume. That's my theory.
Well, if you are really lucky, it just might turn out to be the same strange effect that I recently experienced: I had a new set of tires mounted and when I drove away from the dealer, I immediately noticed this strange vibration/pulsating in the accelerator pedal which was later accompanied by worrying grating noises at certain rpms. Scared the hell out of me, I saw a big repair bill floating toward me in my nightmares.
To make a long story short, it turned out that when the car was lifted the belly pan was ever so slightly pushed upward and vibrated against some components of the exhaust system, which caused the vibration in the pedal and the noise. After providing the correct clearance, presto - problem gone! Smooth as its ever been.
'87 S4 auto
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