Skip the auto shop - Our mechanics make house calls

Q: Engine light and rpm increased while driving

asked by on

When driving the engine light comes on. The rpm jumps 200 to 300 more and drops right after the car jerks and it feels like the engine is acelerating. This happens on and off. When stop at a light on drive car acelerates by itself. Black smoke and fuel smells. Already change trotle body sensor and fuel sensor. Have been check by 2 mechanics can find problem. Car shots off while driving one time

My car has 200000 miles.
My car has an automatic transmission.

This is a common sign of a dirty or failing mass air flow sensor. The mass air flow sensor is a unit in the intake system that monitors air intake as it is mixed with fuel prior to being injected into the motor. When this is dirty or faulty, this causes an imbalanced air/fuel load to be supplied to the motor which results in an over fueling or under fueling situation depending on the conditions. This type of inconsistent fuel supply to the motor may cause a hesitation, loss of power, a jerking reaction, potentially a bot of black exhaust smoke and typically a strong smell of fuel when this sensor is malfunctioning. When this is not working properly, you may also notice a strong smell of fuel. I would suggest having a professional from Your Mechanic come to your home to diagnose your mass air flow sensor.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

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

Get a quote

What others are asking

Q: AC stopped working after refrigerant was added - 1994 Dodge B350

There are a few areas to consider when dealing with air conditioning problems. First and foremost, the system requires a proper full charge of refrigerant in the lines and working fans both under the hood and in the cabin. If...

Q: Leaking coolant - 2004 Chevrolet Silverado

Hi there. Depending on what edition of the Silverado you have the leaking coolant may be coming from the radiator overflow reservoir. It might also be a heater bypass tube that's damaged. The reservoir is used for overflow, as coolant...

Q: Check Engine light is coming on

The problem may not be the Mass Air Flow or MAF. It could be an unmetered air leak, such as a torn intake duct or vacuum line. Check the ducts and make sure they are free from cracks or splits...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.