Hi
My m8's car has developed a problem while its been off the road having some body work done
Have tried a new map sensor on it and checked the resistance of the blue temp sensor
Injectors have been flow tested/cleaned.
The car is over fueling like mad on idle sometimes,then other times its ok at 3% Co,also its running lean when on boost,we checked the plugs after a blast and they were white
Smoking a lot on the over run,grey/black smoke,but idles lovely and running fine

Any ideas please,thinking it could be ECU,anyone had probs like this before???????
Also can welding on a car damage the ECU???????

Thanks