Not running on all cylinders; compression check and spark OK

[bola]

Hi

My 3.0 2003 Z4 is not running on all cylinders. I parked it up last night it was running sweet as a nut...came to start it today and it's not running on all cylinders
This afternoon I have had it plugged in (didn't really say anything even though engine management is on) then compression tested it came back perfect (200 on every cylinder) then checked all coilpacks and sparkplugs which were fine. It also has fuel in the rail. It's running really rough though. Does anyone have any experience with this kind of fault and an idea of the weird problem it may be?

Thanks

 

[AlanJ]

Coil packs can fail under pressure i.e. beyond tick over.....as can plugs. What mileage is your Zed?

 

[sw4nny]

I am not an expert but these symptoms sound just like mine on the e46 330 (same m54 engine)
Also on a friends 03 3.0 zed,both were sorted with coils been replaced.
Mine was also put to bed in good health and woke up ill as yours did.

 

[Smartbear]

An air leak on the intake side could also cause this sort of thing-check hoses/disa valve etc
Regards