Long time debate, I know, but here's some info I'm currently about it....direct from Toyota.

http://www.autoshop101.com/

I'm sure there are ways many have found to get around poor performance by not having an EGR, but for stock set ups it seems optimal to have it functioning. Especially considering today's fuel cost and enviromental concerns.

I'm hooking mine back up!

 

That takes me to the main page, which takes me nowhere.

 

Well in a nutshell, lower combustion temperatures allow for a leaner fuel mixture. A leaner mixture allows for cleaner combustion and a theoretical increase in power.
That theoretical increase in power can be transformed into requiring less fuel to acheive a certain level of performance.
That reduced fuel requirement equates to better mileage.

 

Here is a direct link:
http://www.autoshop101.com/forms/h61.pdf

 

lol... it actually said what I said, but used different words.

 

Uh....you have to actually select a topic and click on it. "Technical Articles", for example.

 

Thanks, Abe. This must be the Cliff's Notes version?