t16coupe

my mate as a fiesta 1.25 zetec fiesta and its down on power and 1 of the plugs keeps turning black on cylinder 3 i have changed the plugs and leads cleaned the airflow meter and lambda sensor but i carnt seem to get to the bottom of the problem i have found a bolt missing at the front of the block could this be anything to do with it take a look at the pic thanks

tabetha

Hard to grasp what that missing bolt holds, but I would do a compression check first.
tabetha