TanK32

May sound a bit daft but was it the bulb or the vehicle they were after! just thinking they may of watched Gone in sixty secs. recently!

Don't know about the plug but, yes it's best to use the lambda sensors as they monitor the amount of oxygen left in the exhaust. The hotwire air mass sensor measures the amount of air coming into the engine, the ECU then calculates the appropriate amount of fuel to be injected, the lambda sensor then checks the exhaust gas to ensure that this is correct and feeds this information back to the ECU so that small adjustments are made. If the Lambda sensors are not fitted then the circuit is an open-loop system (no feed back) with lambda sensors it is a closed-loop system (feedback).

Ref: White smoke, check your brake fluid level, I had a cloud of white smoke out of the back of my v8 disco when doing a brake test. Traced it to the vaccum pipe between the servo and the intake manifold sucking brake fluid from the servo/leaking brake master cylinder. As yours is an EFI it could be giving the lambda sensor in the exhaust a false reading. Only idea not gospel!

Had this happen on a different vehicle, was belived to of been caused by water along the bead freezing and breaking the seal! If in doubt take it to a tyre fitter and get them to put some bead seal on as this sould fill any small imperfections.