I'm still having rough idle/missing problems at 3000 miles on my 2002 C5. I've posted before that I ran 87 octane gas for about 2000 miles. I've since been running Chevron 91 but with no improvement.

I've been advised by a friend that resetting the computer by removing the negative battery cable for 30 seconds will allow the computer to "learn" the correct timing and spark for the higher octane gas.

Truth or urban legend?

Thanks, Kent

 

Idle Learn Procedure


Idle Learn Procedure
Anytime the powertrain control module (PCM) or the battery is disconnected, the PCM loses power, or the PCM is reprogrammed, the PCMs learned idle position is lost. The engine idle is unstable when the learned idle position is lost.

Perform the following procedure in order to return the learned idle to the correct position:

Automatic Transmission
Turn OFF the ignition.
Restore the PCM battery feed.
Turn OFF the A/C controls.
Set the parking brake and block the drive wheels.
Start the engine.
Ensure that the engine coolant temperature is more than 80°C (176°F).
Shift the transmission into Drive.
Allow the engine to idle for 5 minutes.
Shift the transmission into Park.
Allow the engine to idle for 5 minutes.
Turn OFF the engine for 30 seconds.
Manual Transmission
Turn OFF the ignition.
Restore the PCM battery feed.
Turn OFF the A/C controls.
Set the parking brake and block the drive wheels.
Place the transmission in Neutral.
Start the engine.
Ensure that the engine coolant temperature is more than 80°C (176°F).
Allow the engine to idle for 5 minutes.
Turn OFF the engine for 30 seconds.

 

I see that Chuckster has provided your info.

This is definately NOT an urban legend!