i have a 94 sls that all of a sudden started having a minor engine miss. it seems to happen around 1-2 thousand rpm range the most. i have replaced the wires and the plugs are new. i have checked the coil towers and they seem to be fireing fine. if i drive the city i can realy feel it but on the highway it clears up or if it does happen i can punch it and it clears up untill i get down to slower speeds. any idea's