So I drove quite a bit today, went 100 or so miles along M25/M1 to pick up some alloys. All seemed well. Car was parked up for around 20 minuites while I talked to the bloke and gave him my hard earned cash, then I set off again back down the M1
After about 5-10 minuites it seemed to lose power, then on next gear change it wouldnt go past 3k revs. I changed down again and took it slow for about a minuite, then the throttle stopped working! I started worrying now as I was 100 miles away from home

Pulled up on the side and tried to rev it, seemed like it was trying but then gave up, so I turned engine off for a few minuites and started up again, all was back to normal so I drove home. Everythng was fine for the rest of the journey
Whats going on?

Edit: I have an AUM