+1 for boost leak, recently I blew a the last silicone pipe of my turbo exact same thing happened, everything died including steering, car cuts out, would start again bit just rev lower and die, check all your cooler/turbo pipes it might look fine so try jiggling them around thats how I spotted mine, nrma guy told me I had a blown turbo (made a loud noise when it happened so I believed him) so I got it towed it to be told all I needed was a screw driver to fix it