a friend of mine has a 2 wd and cant get the co reading down. If the ECU screw has been over screwed can you tell by taking the cover off, if it proves to be ok what else should we check. It is running greens not sure which chip thanks

 

take the cover off. The screw is just plastic extention of an adjustable resistor on the ECU. You can take the cover off and see if the screw is worn out of if the actual resistor is knackered.

 

thanks