my04 has ever since i got it a year ago had a slight shake/rattle when it starts, usually the first start of the day, but sometimes during the day also.
it sort of shakes after at the start like it does when we turn it off(i did a search and people said the shaking after turning it off is common)
i was thinking possibly a heat shield rattle or possibly motor mount(to explain the shake).
anyone know for sure or have the same symptoms.

 

Sounds like it takes a moment before your idle straightens out. Shaking usually means the engine is turning at less than normal idle rpm.. does the tach agree with my assumption?

 

I have the same problem. Mine is a 06. It's usually when i start it after it's been sitting for a couple of hours. You can feel the shift knob pop a little due to the shake. I would like to know why too....

 

the rpms usually go from 1500 back down to 1000 for a a few moments then drop again to 500ish. i think it is normal there. the shake is more of a whole engine rocking sort of thing.

 

Try turning the a/c off the night before and see if it does it. My car seems to not like the a/c in the morning.

 

anyone else?

 

its the massive torque the engine creates at idle

 

Yep - my '03 does the same. Every S2000 I've driven does the same. Lots of valve spring tension there, I wouldn't worry about it. The car doesn't like running below 1k RPM when it's cold and will let you know about it. I have the TB coolant bypass, and my car is worse with respect to that when it's cold. Everything gets nice and smooth when it's warm though.

 

get an etd and im guessing youll have less of a shake? i feel as this is normal for the car because of the way the engine is positioned.

 

i was just reading through the thread on the timing chain tensioner noise and it said something about the sound of cards in the spokes of a bike,...i kinda have that sound at start up with the shaking...... possibly that???
i cant take it to the dealer from them to do nothing about the issue