you'll find that is normal for this model car and its engine layout given the down time you speak of...at least that is what I have found as my 98 does the same thing.
__________________ http://home.comcast.net/~jmpfleet/Cars/m3r.JPG Current - 04' M3 SMG Convertible SOLD - But never to be forgotten 98 Boxster
Stock w/19" Wheels, stealth K40 front and rear