GM Service Manual Online
For 1990-2009 cars only

Use CNG that meets the specifications of SAE J1616. These specifications place limits on particulates contamination and moisture content. CNG that meets these specifications provides improved driveability and emission control system performance.

CNG that does not meet these specifications may cause fuel system or engine damage. If your dealer determines that the cause of the condition is the grade or quality of CNG used, repairs may not be covered under warranty.