Has anyone else had this problem?

Test drive a vehicle before you buy it . They knew that car had problems hopefully there's a lemon law where you live unless the receipt says " as Is " . All is not lost it may be not that hard to fix .

I did test drive it and it drove fine. I didnt get on it when I test drove it cause I dont drive like that. It happen like 3 weeks after i got it and I only noticed it cause I was passing another car on a 2 lane backroad. Like I said it only seems to happen when I hit the gas hard.

Take it to a proper mechanic and get the vehicle checked out. Preferable a shop that works on Subaru's, be prepared to pay for a repair. If the Check engine light was on, there are codes, the dealer was lying to you. Consider this a learning event.