cars  why


Question by  Katiekatt22 (15)

Why does my Ford Expedition "stumble" while accelerating?


Answer by  setrip (158)

When the vehicle stumbles it can be a number of things associated with this problem. Sounds like you might have a build up in the fuel system. Check your fuel injectors, spark plug connection,spark plug wires, fuel pump, and look for any leaks. Any type of blockage would cause the vehicle to stumble


Answer by  Advisor (1032)

If by stumbling you mean hesitating or losing power, this could be a symtom of bigger problems. First ensure you are in the right gear, especially on steep hills or when you have extra weight. A dealer can provide a full diagnosis, starting with the fuel pump and injectors which may not be providing enough "umph" to the engine.


Answer by  thattractorguy (2970)

It probably needs a tune up. Try replacing the air filter, spark plugs, wires, etc. , and add some injector cleaner to the gas tank or have the fuel system cleaned.


Answer by  myrlin (73)

The mass air flow sensor or meter, known as the MAP sensor, could be in need of replacement. The MAP sensor calculates the density of the air going into the combustion chamber and then calculates the air to fuel ratio. If it is not working properly, you could get a stumble on acceleration.

posted by Anonymous
MAP sensors measure Manifold Absolute Pressure. Speed-Density injection systems use these sensors in conjunction with a MAT (Manifold Air Temperature) sensor and a TPS (Throttle Position Sensor) to calculate air density. MAP and MAF are not the same.  add a comment

Answer by  happytimes63 (865)

There are many possibilities. First try using a good fuel injector cleaner to clean the system. Also try a fuel moisture product to make sure there is not moisture in your fuel. Last the engine may have worn spark plugs and requires a tune up.


Answer by  Amber40 (24961)

Stumbling is probably a sign of a misfiring engine. The most likely cause is work spark plugs. As they wear their spark weakens so under acceleration the extra fuel can actually flood the cylinder and prevent combustion. Do a tune up and check the fuel/ignition system for problems.

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