Engine tuning should be performed by professionals. However, some basic knowledge can help you understand your engine and what is happening with the control program. First, vehicles sold for use on public highways must adhere to emissions regulations. This means that the top priority of the OEM control program is to monitor and adjust engine parameters to achieve a desired emissions output. The A/F ratio at idle or cruising speed is usually maintained at stoichiometric or slightly richer for the best balance of emissions gasses. Wide open throttle acceleration requires a richer mixture for added power and cooler combustion temperatures. Maximum power in normally aspirated gasoline engines is achieved at 12.6:1 A/F ratio. Factory calibrations may not be tuned for this ratio for various reasons which may include fuel economy considerations. Race engines may require an even richer mixture to keep combustion temeratures lower and thus resist pre-detonation (knocking) which is very harmful to an engine. Some engine designs may be more susceptible to pre-detonation and an experienced engine tuner will know how to deal with this situation. If you are in the midwest region, we recommend professional tuning by King Motorsports or Pure Tuning.