How do you fix code P0304 on a Lincoln LS?

Answer 1

That is a misfire code for the #4 cylinder. This is probably caused by the ignition coil for that cylinder (it's on the #4 spark plug) breaking down. If your car has above 60K miles or so, you can bet this is going to happen one or two at a time until ALL the coils are replaced. It's one of the more notorious bugs in the LS. Probably best to just do them ALL (and the spark plugs, too, while you're in there anyway) at the same time, although the cost may make you squeal. But it's either that, or go through it repeatedly every few months until they're all done anyway. Your mechanic will probably give you a break on labor to do them all, and it will end up costing you less, although all at one time.