4.3L Vortec Manifold Gasket Replace/Spider Upgrade

[Mr Bear]

I was surprised. At 150000 miles, the throttle body and the butterfly are still so precise in fit that the slightest misalignment could make such a difference. About two weeks of driving since the final fixes and everything is fine. I'm quite pleased and my mileage is staying in the mid 19 mpg range. I got 21+ on one tank running mostly highway, 65 mph and under. Overall, I'm reasonably happy I did the job, even though it was about 2.5 days of steady work.