Rendy, Has your car ever passed the smog check since you owned it? It is possible that a previous owner has hollowed out your catalytic converter. But more likely I would suspect a problem with the Lambda circuit (and the frequency valve in particular.) If your mechanic isn't familiar with Bosch fuel injection systems to know the difference then find another mechanic or try to educate the one you have. But if you can do that, then you don't need him. :-) Walt Tampa, FL