July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!

Note On Intermittents

Manipulate circuits No. 1230 and 1231. Look for EMI sources, such as sensor wires running along spark plug cables or high power transmitters in vicinity.

Fig 1: Code P056 Schematic (4.6L)

Courtesy of GENERAL MOTORS CORP.

Fig 2: Code P056 Flow Chart (4.6L)

Courtesy of GENERAL MOTORS CORP.