Tachometer slowly started to go about 2 or 3 weeks ago it would work for at initial start up but as soon as id drive out of the drve way it would quit, now it doesn't work at all but when i step on it, it bounces between 1500 and 4000 RPM is ths the sign of a faulty crank sensor? SES light is on and im wondering if this is contrbuting to the startng problem when it is cold, i was told by someone on the forum that it is most likly fuel/air related? any ideas?