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.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing


Experienced Mechanic?

Earn up to $70/hr

What others are asking

Oil leak.
I would start out by taking a large piece of cardboard and park your car over it over night, by looking at the drips on the cardboard this will tell you roughly where the drips are coming from. Sometimes drips...
Multiple misfire codes and hard shifting
Hello. I would start by doing a compression test (https://www.yourmechanic.com/article/how-to-do-a-compression-test-by-robert-tomashek). From the codes (https://www.yourmechanic.com/article/how-to-read-and-understand-check-engine-light-codes-by-jason-unrau) you are getting to the way that is is running and the sound that you hear it sounds like you have a failed valve seat. When...
Headlights come on when off in middle of night draining battery
There are several possibilities that may be the source of this issue - first make sure your headlight switch is in the "Off" position (rather than "Auto" for example). Then remove both the headlight relay and the daytime running light...
Engine will not engage.
If the battery is weak enough, it is possible that it may have enough power to power the gauges in the dash, but not enough to engage the starter. This may also be related to a bad ground connection at...
How fast and how long can I drive with a broken CV shaft?
Once the boot of the CV joint has broke open then over a short time the grease will be washed and slung out of the joint. At the same time you are losing the lube you are getting dirt, dust,...
Air conditioner blows warm air.
The most common cause for warm air when the air conditioner is commanded on is a low refrigerant charge, usually from a leak. One way to check the charge is to have a technician attach a manifold gauge set and...
Battery light and air bag light comes on and off
This may be a voltage regulator issue. The voltage regulator is a unit that regulates the charging of the battery by the alternator (https://www.yourmechanic.com/services/alternator-replacement). When the voltage regulator is not working properly, this may result in the alternator allowing too...
Getting trouble codes p0171 & p0174, truck won't start
This problem would need further diagnosis to see if you are losing fuel pressure or spark when the vehicle stalls like it ran out of fuel. You most likely are losing fuel pressure from a bad fuel pump. Have a...
Dome lights will not turn on when door opened, radio will not turn off when car is off and door is opened.
Hello, thank you for writing in. The vehicle is likely having issues with the door switch which activates/shuts down both circuits. This is going to look like a peg in the door frame next to the hinge. The peg that...

Related articles

The Best Used Cars to Buy If You Live in the Country
Living Living in the country is a whole different way of living. You deal with rough and uneven roads, mud, snow, rain, and ice and you need a vehicle that can stand up to these kinds of conditions with ease....
The Best Used Cars to Buy If You're Towing a Boat
If If you’re towing a boat, the vehicle that you buy is largely going to depend on the size and weight of your boat plus trailer. Most cars, realistically, aren’t cut out for the job. We recommend a pickup truck...
The 5 Safest Used Cars You Can Buy For Under $20,000
The Subaru Legacy, Honda Accord, Ford Fusion, Chevy Volt, and the Volvo XC60 are five of the overall safest used cars you can buy for under $20,000.