Throttle body spacer.

[eternal21]

There is always a ton of info on the web. But 99% of it is crap made up by people who want to sell it to you. On the Interweb you can create fake web pages and fake experts and pretty much fake anything you want. Thats why people need to understand the need for real sources like newspapers instead of reading what some 30 year old guy living in his parents basement writes.

I'm not going to disagree with you. When I research stuff, I usually look at reviews. However, having a little knowledge of these from past experiences.....these were big when older cars used TBI, or throttle body injection, when fuel sprayed into the throttle body. Doesn't do much for other fuel injected systems.
The reviews of them:
http://www.silveradosierra.com/engin...ers-t4921.html
http://www.ford-trucks.com/forums/36...dy-spacer.html

Intake manifold spacers, however...those reduce the temp of the air going into the combustion chamber. As such, these work. There are plenty of independent reviews out there as well as independent dynos to back up the claims.