Engine has uncomfotable flutter in 5th at 3800rpm

[yale]

1970 2.2S

The car goes about 85 or so at 3800rpm in 5th. Motor seemed to prefer that I went either faster or slower.

1st mechanic says, could be running lean.
2nd mechanic says, this is common for the injected cars. "Don't drive in 5th at that rpm. It's one thing if you are driving across the country and trying to save gas, (which is what I was doing), but otherwise put it in 4th. Also your throttle bodies are worn which could have some effect as well."

These seem two different view points, maybe both make sense or...?

Yale

[Flieger]

The second mechanic's statements agree with the first one that the car is running lean at that rpm, because of your worn throttle bodies allowing too much air in. When the revs are higher in 4th gear, the throttle position and rpm put the metering on a different part of the space cam, apparently giving a mixture with proportionally more fuel with the air. Running lean saves gas but causes cylinder head temperatures to rise so can damage the engine if not controlled carefully (like with a fast computer and direct fuel injection).

[yale]

Thank you Flieger.