When I downshift, I get a chirping noise from the engine. Not the tires like a hard downshift. Just if I drop a gear while slowing for a red light or just let off when above about 1800RPM, I hear what sounds like birds chirping rhythmicly in my engine bay. And it's more distinct when the cutout is uncapped, so I'm pretty sure it's an internal problem. Ideas anyone?

 

check the oil. Check the vacuum lines.

 

Valve seat coming lose?

 

Sounds plausible. But wouldn't it also happen at high rpm also seeing as how downshifting brings up rpms?

 

But it doesn't. That's what's weird. I have tried multiple times and it doesn't happen under acceleration. And oil is full and I don't see any loose vacuum lines. Maybe we'll find something when I do my heads/cam/intake swap.

 

I would just take it real easy until then.

 

Think so? It's nothing new. I just dislike it. Kinda reminds me of when I see an old hotrod at a car show that has a roots blower on it, how it has that little chirp chirp to it.

 

Its only when you downshift. Maybe something with the clutch. A little slippage maybe?

 

I dunno. Gonna talk to my tuner/mechanic, but it's definitely odd, since it's rhythmic. Not random, so I'm thinking valvetrain as well, but could be anything. I have a new clutch sitting here to toss in sometime. Maybe I'll do that soon too.