Engine light went up in my Camry 99. Code was 1135. First mechanic replaced air filter and oxygen sensor with another old one. ($95) Light went on again after ~50 miles. Now mechanic forced me to replace oxygen sensor with the brand new one saying that thta's what Toyota recommends. ($224) Light went on again after ~50 miles. Now mechanic wants me to leave my car for a few days and do something else. I will again be out $$$$.
Does this all make sense? To me it's obvious that brand new oxygen filter wasn't needed since light went up again afterwards. Am I right?
Why can't such problem be solved in one shot? Is my mechanic incompetetent?