donald walton

Hi to everyone, I live in London UK,and we have 2 subaru's a 2000,non turbo Impressa 2l auto, and a 2002 Legacy 2.5 auto. sedan. My legacy has been in the dealers garage a week now with engine warning light coming on, they say a sensor problem is the cause, but I wondered if the cat back pressure is the real cause, as the car is just about to come up to 3 years old and I have had it for almost 2 years and always run on unleaded fuel, but if someone put leaded thru it before I bought it then the cat is damaged, and although passes the test, may be marginal, can anyone help, oh, and the heater is shown as on high side ( or so the report from the roadside help said) cheers, Don