For service and parts needs, visit your dealer. You will receive genuine GM parts and GM-trained and supported service people.
Genuine GM parts have one of these marks:

California Proposition 65 WarningSpark Plug Replacement
Spark Plug Replacement
Callout
Component Name
Preliminary Procedure
Open the hood.
Remove the engine sight shield.
Remove the ignition coil. Refer to Ignition Coil Replacement.
1
Spark P ...
Range Selector Lever Cable Adjustment
Note: Adjust the automatic transmission range selector cable while
the transmission and the gear selector are in the Park position only. Failure
to do so may cause mis-adjustment.
Set the park brake and chock the wheels.
Verify the transmission range select lever is in the par ...
Ignition Transmission Lock Check
While parked, and with the parking brake set, try to turn the ignition to LOCK/OFF
in each shift lever position.
For automatic transmission vehicles, the ignition should turn to LOCK/OFF
only when the shift lever is in P (Park).
For manual transmission vehicles, the ignition should turn ...