Diagnostic Aids
An intermittent problem can be caused by:
- Poor connections.
- Misrouted harness.
- Rubbed through wire insulation.
- Broken wire inside the insulation.
- The duct work at the MAF sensor for leaks.
- An engine vacuum leak.
- The PCV system for vacuum leaks.
- An incorrect PCV valve.
- The engine oil dip stick not fully seated.
- The engine oil fill cap loose or missing.
- Poor connection at PCM: inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connection.
- Damaged harness: inspect the wiring harness for damage. If the harness appears to be okay, observe the MAF display on the Tech 2 while moving connectors and wiring harnesses related to the sensor.
- Plugged intake air duct or filter element.
- A wide-open throttle acceleration from a stop should cause the mass air flow displayed on a Tech 2 to increase from about 3-6 g/s at idle to 100 g/s or greater at the time of the 1-2 shift. If not, check for a restriction.