Looking for a little guidance, please. I've got a slight bit of knocking coming from my motor when the engine is still cold - happens only when it's just about to shift to the next gear. I can let the motor sit and idle for a while and it still does it right before it shifts. I can rev the motor in park and not get it to do it. But, after 3-4 mins of driving, it goes away.

I have a slight bit of injector knock (three or four 'knocks') right when the motor starts up but then that goes away quickly.

It smokes quite a bit and idles very rough when cold, then the idle smooths out a tiny bit once warm (or if I increase the RPM a tiny bit). Smokes all the time, even when warm. I'm thinking that is my failed attempt at adjusting the valves.

Any help would be great. Thanks. I might shoot some video of it idling if that helps. Kat

83 240d, about 170k.

Valve adjustment and/or injectors seem like the most likely cause.

That's what I was thinking. Thanks. I just wanted to kinda make sure it wasn't possibly the vacuum pump and then have an issue of damaging the motor.

On a side note, drove it today and no knock at all after the few pings right at start up. I'll do the valves again and report back.

Thanks!

You should be able to hear where it's coming from, but I doubt a vacuum pump noise would change when the engine heats up.