[solved] G'day all

I'm having a perplexing problem with my 1.6 MkV.
*Fuel consumption raises from 0.6-0.7 l/hr to 1.2-1.4 l/hr
*Idle surges, can occasionally stall
*Surging can be felt up to about 2000 RPM regardless of load
*Occasional reduction/loss of brake boost...