Q: The car stalls occasionally as if the fuel is not been pumped

asked by on December 25, 2016

My vehicle occasionally stalls as if I've run out of fuel. My mechanic has change fuel pump twice as well as the fuel filter. Again as soon as the air condition is put on, the car becomes so heavy for want of better word that it doesn't pull as it should.

My car has 252333 miles.
My car has a manual transmission.

It sounds like you may have a fuel supply issue that corresponds to the load put on the motor when you turn the A/C on. This may be related to a faulty MAP sensor. The Manifold Absolute Pressure (MAP) sensor senses engine load and generates a signal that is proportional to the amount of vacuum in the intake manifold. The engine computer then uses this information to adjust ignition timing and fuel enrichment. When the engine is working hard, intake vacuum drops as the throttle opens wide. The engine takes in more air, which requires more fuel to keep the air/fuel ratio in balance. When the computer reads a heavy load signal from the MAP sensor, it adjusts the fuel mixture to slightly more rich than normal so the engine can produce more power. The computer will then retard (back off) ignition timing slightly to prevent detonation that can damage the engine and decrease performance. This may also be caused by other closely related components such as a dirty or failing mass air-flow sensor, a faulty throttle position sensor or potentially a vacuum leak. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.

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