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Q: My truck has trouble starting, and when it does start, it feels like it's choking or struggling to stay on.

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The truck has problems turning on and keeping on after start up. it makes erupt start ons and sometimes misfires. when it's manages to stay on , i press on the gas and it stumbles or doesnt correctly catch up with the gas pedal pressure. When attempting to turn on over and over again it sometimes releass a gas vapor. when coming to a stop and left idling it begins to try and shut off like if i m running out of gas. I ran my check engine light and it marks the canister purge solenoid, coast clutch converter, HEGO H02S sensor fail/lean, and thermatoctor fail.

Would any of these be the cause of it? Or is it the fuel pump? (Didn't show on check-engine)

My car has 265000 miles.
My car has an automatic transmission.

A: The EVAP system prevents fuel vapors from t...

The EVAP system prevents fuel vapors from the fuel tank from escaping into the atmosphere. The EVAP system collects and temporarily stores the fuel vapors in the charcoal canister. The charcoal canister is filled with activated carbon pellets that can absorb the fuel vapors. When the engine is running, the fuel vapors are purged from the canister and burned in the engine.

The vent control valve (solenoid) controls the flow of outside air in and out of the charcoal canister. One side of the vent valve is connected to the charcoal canister. The other side is connected to the vent hose that has a filter or screen at the end and is attached to the car body or frame. In some cars, the vent valve is attached to the canister; in others, it’s installed separately near the canister. The vent valve is controlled by the engine computer (PCM). Normally, the vent valve is open. It closes when the engine computer tests the EVAP system for leaks.

If a leak in the EVAP system is detected, the Check Engine Light will illuminate on the dash and the trouble code related to the problem will be stored in the engine computer. When an air leak is present in the EVAP system, the MAP sensor will not be able to determine the air density, and the MAF sensor will not be able to determine the volume of air entering the engine correctly. This will lead to an over-fueling situation or an under-fueling situation depending on the size of the air leak and engine operating speeds and load. This may eventually lead to the destruction of the catalytic converter as well.

I would recommend having an expert, such as one from YourMechanic, come to your home to take a look at your car to determine why the Check Engine Light is on and if your EVAP purge solenoid needs to be replaced.

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