Afterglow is when the glow plugs continue to operate after the engine has been started. In some cars with afterglow, the car will idle real good for 10 seconds, and then it will run rougher. It starts acting rougher then the afterglow timer turns the system off.

Is this a Euro 1987 300D?? If so, cool! US 300D's (and I believe Euros too) did NOT have afterglow. Once the starter was engaged the plugs turned off.

You might also try some Diesel Purge make by LubroMoly. Connecting it directly to the fuel lines in the engine compartment is the BEST way to run this cleaner (diluting it in full or even nearly empty tank is not as effective). I ran TWO cans of the Purge thru my car and it took away rough running at 1100 RPM. It can do amazing things!

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Brian Toscano