I just looked at the upper and lower intake on my 89' GTU, and I noticed...

On the intake runners, The 2 Primary runners are FILTHY ( as to be expected, I suppose ) BUT, the front-most secondary intake runner is clean as a whistle. From the lower part of the upper intake manifold, all the way thru the lower intake manifold ( It starts to become dirty right before the combustion chamber )

Before the rebuild, the car would fall on it's face a lot, and I couldn't figure why. Uphill was terrible.

Could there be a problem that caused this? I mean, I don't think that that runner should be THAT clean ( the others are quite filthy, as I said before ).

 

I have no idea why they do that, but my '86NA was the same way upon teardown. It had 124K at the time and had died from rear apex seal failure.