Dishwashers, Medicines and Stove Burners

Question

Dear Rabbi, 1) Is there any problem with FLAVORED medicines that contain alcohol (for Pesach)? 2) If a dishwasher has walls that are enamel, can it still be used on Pesach? 3) In general, is a dishwasher only OK on Pesach for people who are lenient with taam lifgam, or is it permitted even for people who are machmir with taam lifgam on Pesach? 4) Is there any concern that food particles are nivla into the walls of the dishwasher during the rinse cycle, before the detergent is mixed in? 5) Should a person run the dishwasher at least once before Pesach to clean it out, or is this totally unnecessary as long as it is clean? 6)Do the grates we put pots on over the stove burners require any kashering? The acharonim imply this is unnecessary.