I had the same problem driving my punto from southern england to scotland. I experienced a loss in engine power so pulled in and called the aa.
As it turned out it was a full injector that was causing the problem.
Thankfully taking it out and giving it a clean worked and i managed without any more drama upto scotland where i changed it.
So to answer your question, you should be alright to make the journey but id recommend getting it checked out asap.
Mark
August 2009