I looked for info on a shake in the throttle as well as a shimmy.....didn't get anything via a search so here goes- I just picked up my son's 03 mcS, I LOVE IT LOVE IT but, It seems to shimmy on acceleration at the high end of the shift. It is very noticable in 2nd at about 30mph.Doesn't do it in higher gears. Feels like the throttle is shaking. I know it isn't......I mean my foot isn't. Anyone shed some light on this for me?

 

CV joints could be binding. My MCS has a vibration upon acceleration sometimes too - though it's not predictable in which gear or acceleration magnitude. Seems that anything less than dead straight tends to promote the occurance, however.

Don't know what you mean by "high end of the shift", could you elaborate? 30MPH in 2nd is quite low RPM, so I wouldn't imagine an internal engine imbalance.

 

It's probably the rev limiter kicking in, cutting off fuel to the engine and making it shudder. This is easily felt through the gearshift lever.

Shift nearer to the top of the torque curve, problem solved.

Please let us know if this helps, good luck!

 

By "higher end of the shift" I mean about 2800 rpm nothing drastic or over-reving..... as for the CV joints, I will have hubby check on that one. But when I have noticed this is at take offs from lights and such, usually already going in a straight line.....It's annoying as heck. It does reduce power with this sputtering shimmi, however I don't see anything in the tach.

 

Do a search for "Yo-Yo".
I think you'll find more info than you every wanted.

 

Don't have a MCS but "yo-yo" sounds right.

 

Rev the puppy,may make it go away