I have a Ford escort 1.8 si, (1997), i have a couple of little things wrong with it.

1, when i accelerate the car judders (like it is misfiring on a HG lead), I have recently changed the HG leads and the coil pack, it might be a connection fault? it worked for a week or so but now its stating to judder. any idea's?

2, I think I have a air lock in the cooling system, is there a easy way of sorting that out.

please help
Thanks
Nick