Mondeo Judder

Hi, this is my first post on here other than my welcome,

I bought a 2003 1.8 mondeo lx petrol the other week. When i start the car it turns over fine and starts, if i turn the car off, nip into the shop, come back out 2-5mins later, you have to turn the key and it takes a few seconds to start and tick over properly. It still starts on the first attempt but just takes longer.

About a week ago when i changed gear it felt like i was in to high of a gear and it started to judder a little bit but after 2-3 judders it went fine. I assumed it was just me going back to a petrol car after owning a diesel for the past few months but today it seemed to be alot worse, I change gear and it judders alot more, again like im in to high of a gear but if i drop a gear, but my foot down it judders the same.

I think its possibly an ignition coil or ignition lead, maybe just a spark plug?

Im wondering if anybody else on here as had the same or a similair problem and could maybe pass on some advice, it would be appreciated.

Thanks