Hello, My 89 420sel Seems To Have A Miss In The Engine. Driving Down The Hi-way Every Once In A While It Drops A Cylinder, Had A Valve Job Done( Good Thing I Did 2 Were Paper Thin On Seat) Car Has 226,000 Miles Does Not Use A Drop Of Oil Runs Great Most Of The Time Except For The Miss, Seems To Last About 2-3 Tenths Down The Road And Goes Away, Then Returns. Speed Makes No Difference 35 Mph To 100 Mph. Start Up Is Sometimes Rough At First Then Smooths Out After A Mile Or So. Also Install A New Fuel Distributor,plugs Wires, Cap, Rotor. Have Not Changed The Coil. Any Suggestions????