Hi i have a saito fa-56 engine ,when the glow plug is connected to battery or its energised the engine transitions and idles fine but when i diconnect it while the engine is running,on high speeds its relativly ok but on idle it dies down,the transition from idle to full throttle is erratic too,the engine kind of sputters or miss,i am using a F series plug i guess its OS,tried two different plugs with same result,am i using the wrong plugs or is it some thing else.....

Thanks

salman