You may be right about the pump but Its impossible to diagnose the problem with the info above therefore its best to take it to the garage and get it checked. Dont drive far or for a long time without getting the problem sorted as it can worsen.
Good luck
I do not have a tv, neither do I use my laptop to watch live television of any sort, but TV licencing keeps sending me threatening letters , asking me to purchase a licence? But I dont understand why