Hey thanks , this is all good stuff , I have been a marine diesel tech for 20 years and this 300d is shurely different, why do they want to restrict fresh air into any diesel?? this will surely mess things up , the air flapper on mine seems to choke off 3/4 to 7/8 of air flow coming off idle from about 900 to 1800 rpm intermitintly when the flapper does not move we run great , when it pulls vac to the flapper sol we chug & smoke untill the rpm goes up past 2000 then runs fine, was thinking of just dropping flaper vac line & driving with unrestricted air flow?