Engine kick on idle - 1986 300SDL 261k
 

Maybe it was just the cold this morning (17F), but my engine "kicked" a couple of times while idling during warm up, and although it went away after I pressed the accelerator and revved it up to 1000rpm, and the engine eventually got warm, it's still spooking me.

What could it mean?

Bad fuel? Needs an oil change (about 1/2 way through 3k rotation), fuel filters?

I dunno. Creeping me out.

The 603 can suffer from incomplete combustion as it warms. It's dependent on engine condition and glow plug condition.

It's also dependent on how long the glow plugs have heated the precombustion chamber.

You can experiment with a 30 second glow time to see if it improves the situation.

You can also bring the idle right up to 1200 rpm on start and hold it there for 30 seconds.

You can replace all the glow plugs with a brand new set.

You can also spend the money and get an "afterglow relay" that will keep the plugs on after start for a bit.