87 420 sel missing badly after warmup

[denismitchell]

let's try this again, i know there has to be a benz guru or two out there who can guide me in the right direction. i'v got a 87 420 sel that misses after it warms up, i';ve change the spark plugs and no luck. i didn't want to start throwing a bunch of money for nothing, any help or suggestions would be greatly appreciated