6/79 LC all emissions intact. Engine runs great, idles smooth. Has no effect on drivability. But this sound is getting worse. I’ve been chasing it for months and can’t find it. I have two videos. One while I’m driving and one while I’m standing over the engine. The one while I’m driving sounds like a whistle. The one over the engine sounds more metallic. My vacuum is within spec and very steady. It only happens while the engine is warming up, but not right away, kinda like it has something to do with the emissions equipment. Maybe just after starting the engine something moves and makes the noise, then when the engine gets to full temp it moves again and the noise goes away. Most of the time it only does it when the throttle is just off idle. Like just enough power to maintain speed. But I can make come and go with the throttle. I sprayed the manifold down looking for vac leaks with no luck. Any help would be greatly appreciated. If you need more information let me know.
While standing over the engine.
While driving.
While standing over the engine.
While driving.