* Fuel Pump Issues (but not total failure): The fuel pump might be weak, delivering insufficient pressure to the injectors. It might only work intermittently or be struggling under pressure. This is the most probable cause.
* Fuel Pressure Regulator: This regulator maintains the correct fuel pressure. If it's failing, the pressure may be too low, allowing the engine to stall when the added gas is consumed.
* Fuel Injectors: One or more injectors could be clogged or failing to open properly. The extra gas might temporarily overcome this until it runs out.
* Fuel Filter: While less likely given the temporary fix, a severely restricted fuel filter could be contributing to low fuel pressure, especially if combined with a weak fuel pump.
* Cranking System Issues (less likely): While the engine runs when the extra gas is added, a weak battery or starter could mean that the engine needs that extra fuel to maintain combustion.
* Ignition System (less likely): Problems with the ignition system (coil, distributor, wires, etc.) could also cause stalling. However, this is less likely because the engine runs for a while after the gas is added.
Troubleshooting Steps:
1. Check the Fuel Pressure: This is the most critical step. You'll need a fuel pressure gauge to measure the pressure at the fuel rail. Compare it to the specifications for your 1995 Suburban's engine. Low pressure points to a pump, regulator, or filter issue.
2. Inspect the Fuel Filter: Look for rust, debris, or significant restriction. It's easy and cheap to replace.
3. Check the Fuel Pump Relay: This relay controls power to the pump. Ensure it's functioning correctly.
4. Inspect the Fuel Injectors (Advanced): This requires more technical knowledge and tools. A faulty injector can be difficult to diagnose without specific equipment.
5. Check the Cranking System: While less probable, a weak battery or starter can cause similar issues. Test the battery voltage and observe the starter's performance.
Important Note: Adding gas directly to the fuel system (even to what appears to be a carburetor) is dangerous and could cause a fire. Do this only as a diagnostic tool and avoid doing so in the future. Proper diagnostics are crucial before attempting repairs.
