Hi can i ask ,if any members with the W103 engine ever used the 4 earth bosch spark plugs. As i have read some place that the m103 is fussy about the type of plugs it uses. At first when start the engine it is like missing very slight ,but it is running fine after ,tick over is fine on the road its fine.Only have it at start up. Or should i look in another place for the fault.Can anyone say what it might be,other than these plugs .

 

that engine you should stick to a non resistor spark plug.Bosch quality has gone down hill,I run either NGK or Denso plugs.

 

Oldsinner thank you . As my thoughts at this point ,are as you have said in your post. I have been shopping around and checked it out, and yes they must be resistor less plugs . And the Super 4 plugs do have resistors. Just going to order 6 more NGK BP6EFS plugs. Thank you for your help.