Originally Posted By: exranger06
Tampering with emissions equipment IS illegal in all 50 states, even if your state doesn't have emissions testing. Whether or not your area actually enforces that law is another issue entirely.
This is correct. It is illegal under the Clean Air Act anti tampering rules to remove emission equipment:
(1) Section 203(a)(3) (42 U.S.C. 7522(a)(3)) is amended to read as follows:
'(3)(A) for any person to remove or render inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under this title prior to its sale and delivery to the ultimate purchaser, or for any person knowingly to remove or render inoperative any such device or element of design after such sale and delivery to the ultimate purchaser; or
'(B) for any person to manufacture or sell, or offer to sell, or install, any part or component intended for use with, or as part of, any motor vehicle or motor vehicle engine, where a principal effect of the part or component is to bypass, defeat, or render inoperative any device or element of design installed on or in a motor vehicle or motor vehicle engine in compliance with regulations under this title, and where the person knows or should know that such part or component is being offered for sale or installed for such use or put to such use; or '
From here:
http://www3.epa.gov/otaq/about/faq.htm#question13