Chevy Suburban Forum (GMC Yukon XL)
Please Please Help..
1999 Suburban K1500 LT 5.7 Vortec with the newer Spider style. Completely Stock other than added a second battery with a relay.
Background: Fresh Rebuild after previous head gasket and 2 cracked heads.
Issue: P0134 P0154 and seem to be in Open Loop all the time...