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Hooray, I'm wrong again!

I was expecting to find bad things wrong with the little red Civic... specifically a valve in the cylinder head going bad. I checked over all of the ignition parts, including using an oscilloscope to find this misfire -nothing. I did a compression test and a leak down test on the engine, and I found nothing wrong there either. I checked over the PCV system since it runs through the #3 cylinder... nothing.
I sprayed carb cleaner over every intake part with the engine running, listening for a vacuum leak... nothing.

Luckily I have access to other expensive diagnostic tools, like this: (pic after jump)

Accessing a vacuum port, I filled the intake manifold with the smoke that this little gem makes and watched, and waited, and watched.

Low and behold I see smoke coming out from somewhere it should not, right above the #3 intake runner, from the throttle body shaft bushing (I took a pic with my phone camera but it didn't come out).

Unfortunately the only way to get this part is to buy another throttle body, which is $400 new. I'll try to find a used one which doesn't leak, but we may have to live with this. It only runs rough sometimes when you short-shift to 2nd with a cold engine, so we can work around that.

So I got all worked up over a tiny vacuum leak... at least, so far that looks like the culprit.