Car jerks about when driving?

the ford zetec coils are pretty crap and dont last long so if its done enough miles to warrant a cambelt then it is probably the coil. but other things to be aware of are maf sensor {m air flow} because this can cause the engine to run too rich or too lean which causes missfires which makes it jerky, when they start to go wrong its ust the odd judder here and there mainly when in traffic with little throttle movements, if it is the coil its normally when your booting it around and is much worse the hotter it gets. it could just be a dirty coil as dirt absords moisture from the air which allows the sparks it generate to track along the outside of the coil rather than actually going along the ht lead