Vacuum gauge instead of Scangauge?

[cheapybob]

On the old cars, that's what you'd use.

I think a TPS reading is much better, though. For example, on my Saturn, I know that TPS 11 will give me about 65 mpg on flat with no wind, so if I'm getting onto an expressway, I give it TPS 17 or so to get into traffic, and when the speed gets to 65 I back off to TPS 11.

Vacuum sorta tells you that, but I'm not sure how well.