2007-2014 Cadillac Escalade vehicles equipped with a 6.2L engine may exhibit a rough idle and rough running engine, with DTC P0171 and/or P0174 stored (fuel trim system lean, bank 1 or 2).
Inspect the PCV tube for a vacuum leak on the left side of the engine. The engine cover can cause a rub-through on the PCV tube located at the left rear of the intake manifold, just above the fuel line connection. If this is the case, replace the PCV dirty air tube and cover it with a conduit to protect against repeat damage. Reset the idle and perform a fuel trim retest.
After replacing the air tube, cover it with a conduit to protect the tube.