For your reading pleasure.....

United States
The clean-up of all MTBE in the U.S. in the form of groundwater and soil contamination is estimated to cost as much as $140 billion, including removing the compound from aquifers and municipal water supplies and replacing leaky underground oil tanks. Some controversy centers on who will pay the costs of this remediation.

Recent state laws have been passed to ban MTBE in certain areas. California and New York, which together accounted for 40% of U.S. MTBE consumption, banned the chemical starting January 1, 2004, and as of September, 2005, twenty five states had signed legislation banning MTBE. (A table of state by state information, as of 2002, is available here at the U.S. Department of Energy website.

In the year 2000, the U.S. EPA drafted plans to phase out the use of MTBE nationwide over four years. Upon taking office, the Bush administration cancelled those plans. In April of 2002, a California jury found several oil companies guilty of irresponsibly manufacturing and distributing MTBE, stating that the companies acted with malice in failing to warn customers about the dangers of MTBE contamination. There are hundreds of other lawsuits currently active regarding the compound. An amendment to provide blanket immunity from MTBE-related lawsuits was inserted into the House version of the 2003 Energy Bill, which did not pass.

The Energy Policy Act of 2005, passed in the House on April 21, 2005, did not include a provision for shielding MTBE manufacturers from water contamination lawsuits. This provision was thought by some to be a priority of Tom DeLay and Rep. Joe Barton, chairman of the Energy and Commerce Committee. [6] This bill also includes a provision that gives MTBE makers, including some major oil companies, $2 billion in transition assistance as MTBE is phased out over the next nine years. [7] Due to opposition in the Senate, the conference report dropped all MTBE provisions. The final bill was passed by both houses and signed into law by President Bush. [8] The lack of MTBE liability protection is resulting in a switchover to the use of ethanol as a gasoline additive, which is in limited supply in April 2006. Some traders and consumer advocates are blaming this for an increase in gasoline prices. [9]

Certain patents important in the manufacture of MTBE are not held by American companies; for example, United States patent 5536886, Process for preparing alkyl ethers [10], is owned by the Finnish company Neste. (The same corporation also went on to patent the replacement of the MTBE process, an octane production process trademarked NExOCTANE.)

Gnarls.

Yes he can! <img src="/forums/images/graemlins/zombie.gif" alt="" /> ... of course he may be totally full of hot ca-ca!! <img src="/forums/images/graemlins/lol.gif" alt="" />

Gnarls. <img src="/forums/images/graemlins/butwiggle.gif" alt="" />

I've heard lots of Weber proponents say they can easily be tuned to run cleaner than stock systems.

Either way, I'd like to see some numbers for comparison.

Interesting.. then can you explain why gas mileage at high elevations DECREASES?? When I did the Dusy-Irshim trail (peaks at 9700 feet) above Fresno, it's 31 miles long and I burned up nearly 18 gallons of fuel. The carb'd V-8 (and I warned them before we got to the trail) got less than 2 miles per gallon!!
Gnarls.

The EGR adds back burned gasses to the intake charge, thereby taking up some of the space that a fresh air/fuel mixture would otherwise fill. In this way, it helps extend fuel mileage. The burned gasses obviously can't be burned again, so in this way it helps control the flame front (burn rate) of the igniting air/fuel charge. This helps control pinging.

The EGR is a good thing to have operating correctly, unless you are a looking for all-out horsepower and performance with no requirement for fuel economy or emissions control.

Mike in AR

I'd guess that the operator senses the power loss and pushes the pedal harder to compensate. The weight and rolling resistance of the vehicle doesn't change at altitude, regardless of how much power the engine makes.

Mike in AR

I always wondered how this worked, but I guess I never really thought about it. the FSM is pretty good about explaining how these systems work. probably ought to give it a read, but what you say makes sense.

I'm not sure how it affects emissions, though.

about it controlling the flame front -- this leads me to think that increasing EG will reduce the burn rate?

here's a question for you -- what happens when people add hotter ignition systems? does this cause more or less pinging without compensating with more fuel?

I was being sarcastic and there's a good chance that a well tuned engine will run cleaner without some emission's devices. But it's federal law that you cannot remove emission's devices whether they work properly or not. In states like NJ you need to pass emission's and pass a visual inspection to make sure your vehicle has not been altered. My 96 SS Camaro has headers but I retain the EGR, dual cats and AIR setup. My 69 Camaro requires an older style AIR setup but no EGR. If your vehicle originally came equipped with EGR and AIR then you must retain it and it should be functional. Even if your state doesn't test it, it's illegal to alter it. In some states, they will take your vehicle off the road if they find it has been altered. Plus, a properly maintained emission's engine will run better with everything working. People remove stuff because they think it's cheaper than fixing the right way. When the rest of the states eventually adopt the tougher emission's there will be a lot of people with altered vehicles that won't pass and won't be allowed on the road. It's only a matter of time.

And from what I see on the VA EPA page, EGR is required if it was originally installed by the manufacturer. If your local inspection facility didn't notice it, they could get in trouble just like you can for not having it.