Some GM Trucks Are Lying About How Much Fuel They Have

General Motors is looking into a fuel system issue that could cause certain heavy-duty pickups to stall, even when the fuel gauge says there’s still gas left in the tank.

General Motors is investigating a fuel system issue affecting certain 2025 and 2026 Chevrolet Silverado 3500 HD and GMC Sierra 3500 HD chassis-cab trucks equipped with the 6.6-liter L8T gasoline V8. According to a February 2026 preliminary service bulletin, some trucks are running out of gas even when the dashboard says there is still fuel in the tank, but others have a fuel gauge showing empty, even though there is still fuel in the tank

These chassis cab trucks use a dual-tank setup with a combined capacity of approximately 63.5 gallons. Fuel is transferred from the rear tank to the front tank, with the engine drawing from the primary tank. The fuel gauge reflects the total volume across both tanks. If the transfer pump fails, the front tank could run dry even while fuel remains in the rear tank.

That transfer process may not be working as intended. If fuel fails to move from the rear tank to the front tank, the engine can run out of usable fuel even though gasoline remains available in the secondary tank.

The issue appears limited to chassis cab variants, which are typically upfitted as flatbeds, utility bodies, tow trucks, and dump trucks for use in commercial applications. GM has not said how many trucks could be affected. In the meantime, owners or operators who experience stalling or inconsistent fuel readings may want to keep tanks topped off more frequently until a permanent solution is announced.

So far, GM has not issued a recall and has not identified a final repair. The company has instructed dealers not to replace parts until the root cause is confirmed.

This is not the first time GM’s heavy-duty pickups have faced dual-tank transfer concerns. In 2024, a similar problem affected certain 3500 HD models equipped with the 6.6-liter Duramax L5P turbo-diesel engine. That problem stemmed from a blockage in the fuel transfer inlet port at the tank sender; at the time, GM suggested a replacement part.

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