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2000 GMC Yukon 5.3L Engine Misfires and Fuel Issues: P0171, P0174, P0300, P0151 Diagnosis

Model: 2000 GMC Yukon Fault Code: P0151 Posted: 2008-01-17 21:34

I recently started having serious engine problems with my 2000 GMC Yukon equipped with a 5.3L V8 engine. When I turned the key on this morning, the truck would barely stay running—eventually failing to move out of my garage. The OBD-II scanner shows multiple fault codes: P0171 (Rich Mix Bank 1), P0174 (Rich Mix Bank 2), P0300 (Random/Multiple Cylinder Misfire), and P0151 (Oxygen Sensor Circuit Malfunction on Bank 2). The engine cranks but dies after a few seconds of rough operation. Acceleration causes severe hesitation, sometimes leading to complete stalling. After repeated attempts, the truck won’t start at all. I’ve already replaced fuel filter, spark plugs, and wires, and inspected vacuum hoses—yet the issue persists. The problem began exactly one week ago, and I’m concerned it may be related to a recent accident (three to four weeks prior), though the truck ran fine afterward. I suspect either a wiring fault, sensor failure, or fuel delivery issue. What could be causing this? Any advice on next steps?

Related fault codes
P0151P0171P0174P0300
Comments (5)
Anonymous 2008-01-18 08:24

Begin troubleshooting with the Mass Airflow (MAF) sensor, check for vacuum leaks, verify fuel pressure, and inspect upstream oxygen sensor wiring, connections, and operation on Bank 2. These are common causes of P0171, P0174, and P0151 in this model year. Ensure all electrical connections are secure and dry.

Anonymous 2008-01-18 09:13

I've removed the spark plug wires and found that all ends show a white coating on the connector tips. I was told this indicates poor spark due to lack of ignition, leading to flooding and engine stalling. While it's surprising that every wire has this appearance, I'm now concerned about whether this is a widespread issue or just one symptom. After reading many forum posts, it seems like multiple components could be at fault—does anyone have experience with this specific white residue on 2000 Yukon spark plug wires?

Anonymous 2008-01-23 07:03

The scanner shows P0171, P0174, P0300, and P0151. I replaced the fuel filter, spark plugs, and wires, and checked the vacuum hose on the fuel regulator—yet the fuel pump doesn’t activate at all. Even after replacing the pump with a new one, no fuel flow occurs. The battery has been recharged, but there’s still no power to the pump or fuel delivery. No fuel passes through the filter. This issue started exactly one week ago. I’m wondering if the recent accident (3–4 weeks prior) could have damaged the fuel system wiring or pump housing. Any suggestions for further diagnostics?

Anonymous 2008-01-23 08:20

Many 2000 GMC Yukon models are known to suffer from degraded wiring harnesses, especially in the fuel pump circuit—this can result in intermittent power loss and engine failure.

Anonymous 2008-02-17 02:10

The white powder on spark plug wires is typically caused by heat cycling and moisture condensation. Over time, this residue can degrade electrical connections. I recommend using dielectric grease at all connector points to prevent moisture buildup and improve conductivity. While it may seem like multiple issues are present, starting with basic checks—like wiring integrity and fuel delivery—is often the most effective approach. A service manual will help guide a systematic process of elimination for this 5.3L engine system.