Silverado 1500 2WD V6-4.3L (2007)
15. For vehicles equipped with 4WD perform the following steps, remove the left front CPA retainer.
16. Disconnect the engine wiring harness electrical connector (7) from the left front HO2S electrical connector (8).
17. Remove the left front HO2S electrical connector clip from the fuel line clip (2).
18. Remove the catalytic converter to muffler nuts.