2014 Silverado 5.3 #3 cyl dead miss at idle only.

[LeBaron]

Plug, wire, and coil is good. 190psi compression.  Replaced all fuel injectors. Rockers moving normal visually during cranking with valve cover off.  #3 cylinder is not one of the cylinders that drop out during DOD.  192k miles.  Runs great off idle. OBD II shows no missfire above idle driving down the road but as soon as you come to a stop, #3 cylinder has a dead miss.  Any ideas?

[mjm-1957]

What about a vacuum leak? Has the intake manifold ever been off with close to 200,000 miles? Spray some brake cleaner around the intake manifold at number 3 and see if it straightens out.You could also monitor live O2 data while spraying brake clean and watch for bank one sensor one changes.