This info is purely 'quoted' from a friend of mine who has a 94WRX.

He went to have it dyno'd and they said they could not do it cos it was back firing! The plugs and coil packs had to be replaed. He has done this and also replaced the 'vacuum' hoses which lead to the turbo and dumpvalve (again not sure what these are)

He says now he is not boosting as much and he went through like a 1/4 tank of petrol in only a few miles!! There is no smell of petrol or any leaks. (that seems alot of fuel!!)

Anyway, he has asked if anyone can shed any light.

regards
Lee

 

Your mate may have put the vacuum hoses back on incorrectly.

 

How do these work then? Not familiar with them