Think i might have damaged my turbo when i bought the car about 3 weeks ago it was nice, put my foot down and it would throw me back, now it's still fast but not as fast, do turbo's gradually go or could this problem be something else?

Also when i open the bonnet, there's all oil on the inside of the bonnet, where could this oil be coming from? i revved it with the bonnet open and the oil cap doesn't lift up (thankfully) could it be the turbo oil seals? as i know these need replacing.


Any info appreciated