Ford Focus 2002 1.6 ghia Engine problems

Hi I have a car that does not like long drives

Live in Rochester and driving to maidstone a few miles

Noticed that when there is 3000 revs there is a burning smell coming through the vents, engine starts to grumble, then end of journey turn the engine off, few minutes later try and start car, it starts then cuts out fews seconds later, hour later car cooled down, car starts perfectly.

There are no misfiring at all, engine runs smooth, had engine serviced month ago.

Any ideas ? before I start guessing and spending money where it is not needed to be spent on.

Thanks for any info guys