I have just bought a Mazda with a 12a motor . Serviced it and it runs a dream but on engine run over when using enghine braking it backfires just a little - is this normal.

I am in UK and some of the products you mention are not knwon to me .. It is a low mileage engine and Igive it some stick- do I need a fuel additive to proevent carbon build up in the motor

Thanks

Paul

 

The air control valve has a ANTI AFTER BURN valve internal to it. It might be bad or needs testing per the online fsm.