Exhaust Leaks

1987 Chevrolet Step Van P20, 7.4 W, Automatic, 400/M40SECTION Exhaust Leaks
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 1994 GMC Vandura, 1994 GMC Rally, 1994 GMC Pickup, 1994 Chevrolet Sportvan, and 1994 Chevrolet Pickup. However, it is still accessible from the selected car via links, so may be relevant.

If exhaust system has large leaks, exhaust system negative pressure pulses can cause outside air to be drawn into system and past O2 sensor. Vacuum or crankcase leaks can also cause a lean condition.

If Code 44 is intermittent, see INTERMITTENTS in appropriate TESTS W/O CODES article in this section. See below.

  • H - TESTS W/O CODES - GASOLINE (for "C" & "K" Series)
  • H - TESTS W/O CODES - GASOLINE (For "G" & "P" Series)
CODE 44 TERMINAL & CIRCUIT WIRING IDENTIFICATION

Application PCM Terminal Wire Color
"C" & "K" Series
5.0L A/T
Oxygen Sensor Signal A10 Purple
Oxygen Sensor Ground A12 Tan
5.0L M/T
Oxygen Sensor Signal D7 Purple
Oxygen Sensor Ground D6 Tan
"G" Series
5.0L A/T
Oxygen Sensor Signal A10 Purple
Oxygen Sensor Ground A12 Tan
Fig 1: Code 44 Schematic (5.0L) Lean Exhaust Indication
G91H07378
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.