Heya, trying to figure something out, though somebody might be able to help.

I recently changed my sparkplugs, and since then I feel a subtle but noticeable fast vibration between 1000-2500 rpm. At first I thought it was my imagination, but it's definitely there.

When I take off from a light at any throttle, I feel a weird harmonic that wasn't there before, and above that rpm it goes away. Also, when the car is warmed up, if I'm at idle in neutral, clutch out, I can feel the same vibration through the brake pedal.

It doesn't seem related to the general vibration at idle, which is subtle anyway. This is much faster and sharper than that, as if the engine was hitting something at each revolution. Higher than 3k the car feels completely normal.

By feeling I'd compare it maybe to a cell phone vibrator.

No other symptoms, no lights or loss of power or hesitation. I did the 20-brake-stomp-reset and the 30mph motor-mount test, which showed no hesitation.

I'm going down to the car to check on the plugs, motor mount and everything else visually, but thought I'd leave this here if anyone has ideas.

Thanks,

 

Bit of an update, visually everything seems fine, and there's no lack of power or other symptoms. Rechecked all connections.

Can someone help me out though: on your car, with the engine idling warm, if you put your hand on the throttle body, does the vibration feel lumpy and erratic or rapid sharp and regular?

Thanks,