Engine trouble!!!! Had my impreza turbo UK w regards (2000) and was driving along at around 110mph when I heard a quick noise which initially I thought bottom of car had scraped as some parts of road had slight humps,as car slowed down I started to accelerate again and there was no power and the boost gauge was only going as far as the 0 it's as if the boost is escaping and car is so sluggish and doing odd misfire.when in neutral and stationery and I rev engine you can hear the turbo but when I set off it just hasn't got no power.......any ideas or info welcome as I'm new to these cars..........:\