No light at all? Generally when your car has any misfires it is going to throw an engine code. I would take it to autozone anyway and ask them to can it. Your light could just be out. As far as the bucking, have you replaced the spark plugs any time recently? Could be the motor isn't getting spark. I would start there then move on to bigger things.
Search Dodge Caravan Questions
Are you a UK consumer? CarGurus now has a discussion forum in the UK.
Dodge Caravan Experts