Greetings.
About a month ago, I burned the #3 exhaust value when the seat came loose. Before the catastrophe, one mechanic told me that the whistling sound was normal in older cars. Yikes! This was the third set of heads I've replaced in less than 30K miles.
I've wondered if the engine was running way too lean. The air-flow regulator adjustment screw is all of the way in. I've searched for intake leaks, but none have turned up. Another mechanic believes he can adjust the mixture by changing the air-flow meter spring adjustment...which he has done twice, but the engine still shows signs of running lean. The values are tight after a few hundred miles.
I'm frustrated enough that I'm considering replacing the engine with a carburetor fed model.
1) Has adjusting the return spring of the air-flow box been shown to be fruitful? 2) Is there some advice available for locating air leaks? 3) Do older AFC engines run lean and there's nothing we can do about it?Cheers.