Can anyone help?
I have a 525dse runs great then suddenly it starts running sluggish, wont accelerate and then white smoke bellows out of the exhaust with red hot embers flying onto the road. After I stop and turn the engine off it runs ok again for about six days. Could it be an injector? Steve

 

Can you pull codes? An injector should pull a knock code on a cylinder. But white smoke is usually a sign of coolant leaking somewhere.

 

Red hot embers? Cat converter?

 

Agree that white smoke indicates coolant entering the combustion chamber.

 

red hot embers? blimey!

Where in the UK are you? Definitely see if there are any error codes.

 

Hi, thanks for the reply, I live in Preston Lancashire. Took car in today to local garage, codes came up but just glow plug and air mass sensor. When it was running a bit rough a few months ago I had a new air mass sensor fitted but it carried on running sluggish when moving off so put old one back on.
It's a mystery, once the white smoke had gone after turning the engine off it goes like a rocket.
Steve

 

Hi, been in garage today, only codes air mass sensor and glow plugs. I had a new air sensor fitted 6 months ago when it was driving sluggish but it did nothing to improve it, so put the old one back on.
Thanks, Steve

 

Where did you buy that MAF (Mass Air Flow) sensor?
If it wasn't original BMW part, I'd throw that out and get an OEM part.