well this is my first post and not sure if its in the right place?....so here goes

just purchased a 93 l reg impreza wrx.....now as i know absoloutly nouthing about these cars i thought id ask yous.....the experts
i have a problem? the problem is?wene the car is idle,ing for maybe 2 to 3 mins and afterwards you blip the throttle theres a puff of light smoke from the exhaust.....happens at lights and so on...is this normal?
it takes a couple of revs then it clears altogether?...what could be happening
as i say first ever turbo car so dont know a lot about them?

 

Could be turbo bearings gone or alternatively pison ring wear, for the latter worth getting a compression test to rule out.