99 SLK 230,,from 64k miles when I first bought car; when under heavy acceleration in 2nd gear (5 speed manual) ck eng. light comes on; resets after about 3 cycles on, off now still does this 108 k miles; changed following; plugs wires, coils fuel filter, cleaned maf map sensor; seems to ONLY do this under heavy acceleration in >>2ND gear<< only use premium gas; gas cap seems ok any other things I could check; auto supply & mech used code reader & says int. miss on various cylinders; o' reileys showed int. miss on cyls. >1234; any help of advice would be appreciated; only does this when in 2nd gear under heavy acceleration; Thanks in advance, Steve

 

cam position sensor? vacuum leak?

 

Yeah, it pretty much might be a vacuum leak problem. And also check if your gas cap is loose or damaged.