this problem surfaced suddenly it did not give any indication there was a problem . The whisteling noise occurs when the throttle is depressed. the car will slowly accelerate by " feathering" the gas peddle. If I depress the accellerator more than just a little it sounds like a Quadrajet with the secondaries open but the car slows down and loses power, if I full throttle it it knocks an pings real bad. It sounds like a bird whisteling under the hood , I alo noticed it runs a bit hotter when you try to get the car up to highway speed. I could accept the catalytic converter in theory but what about the whisteling soud that sounds like a vacum leak??