Hello, I need help. My 87Turbo runs overly rich....won't pass emissions because of unburned hydrocarbons....tailpipe very sooty....you can see the exhaust....original catalytic converter totally plugged up with soot which I first thought to be a turbo problem as engine would act as there was a governor on it under load. Starts and runs Ok until higher rpms when there is a hesitation which you can "feather" the gas pedal to get a little more speed out of car. Really would like to repair as car is a pleasure to drive and before this problem would surprise some people with performance for a Volvo!!!!!!