Haven't done anything.
It's at the shop having the aero-mirrors and rub strips painted.
Should have it back soon.
Gonna check the TPS and a few other things.
Needed a break anyway, it was getting very frustrating.

Mike, I may take you up on that.
I'll let you know.

 

So what eventually solved your issue? I'm chasing a similar whistle combined with a significant miss at idle that smooths out around 2k rpm. This is after an intake powdercoat/refresh.

 

It was a vacuum leak.
I ended up running a smoke test on it.
It turned out to be several small leaks from driver side intake gasket.
Had some gaskets special made....the whistle stopped.
Hasn't whistled since....knock wood.

 

For my issue, the Powdercoating of the intake runners had warped the flanges that mate to the intake ports of the head, so I had to remove the intake & put the runners on a belt sander to re-flatten. One was so bad you could see light under it & it failed the vacuum/smoke test.

 

Had one do exactly this a few weeks back. Took a good amount of time to get the mating surfaces flush so they would seal with the factory gaskets.

 

Exactly Sean. Exactly. My warp was at Runners 3 & 4 (#4). Used a Firework punk to find the leak, verified it with light as well: no wonder that sucker whistled so loudly!

 

I pressurize the intake and listen for the air with a mechanics stethoscope. If it holds pressure for a bit of time then it's good. If not, well ya leaking.