Hi everybody,
I should start by saying that I'm not the most mechanically inclined person, so bear with me (as this might be a dumb question or have an obvious answer)

I picked up a 97 gtp with 220k kms on it for around 3 grand in November. It needed its share of maintenance (filters, fluids, headlights, tires, etc) but nothing too big. Up until yesterday it's been great and a blast to drive, but when I was coming home from school on the back roads and I put my foot into it, it flew up to 80-85 km/h and wouldn't go any higher under heavy rpm and full boost (which I quickly let off).

I took it around the block again and gave it another go, and it didn't happen again–it was totally smooth. My guess is it's to do with the transmission, but I honestly have no idea anybody have any input? it would be greatly appreciated.