When you sent me that email, I kinda sat there and scratched my head. . . . who's that??? Sorry, about that.

No your problem (had you not given us the solution) is not the DTC19. With a missing/rough running, I bet on a bad plug/bad wire/dirty/fouled injector.

Just because you changed wires and plugs, one or the other could still be bad. Same with the injector.

A STORY: saw Pat (Exclusive Motors) diagnose the same problem with a S420. He pulls the ignition wires while running holding the wire over the plug slowly pulling away until no 'spark'.

On this car, nothing changed, so after a little testing, bad cyclinder was number 4. Was a shorted/open plug. Wouldn't have believed it if didn't see it myself.

The clue: the car would idle rough but when when forced to 2000 rpm, then back to normal idle, the car was as smooth as glass for about 1-2 minutes until the plug fouled. That's how he knew it was a plug not the plug wire.

But this same car had two (2) bad wires; they were open!

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Regards . . . . JimF
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'94 S500 Cpe

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