Skip the auto shop - Our mechanics make house calls

Q: Engine starting to stall, surging, and poor gas milage. Misfiring

asked by on

My engine starts to stall and then surges at any rmp or gear. It begins to stall and then surges at idle. Vehicle power it greatly reduced. Misfiring. Vehicle gets 11 mpg when it should be getting 19/20 mpg. Repairs Done: 1. Catylitic converter 2. O2 Sensor 3. Tune up with plugs, wires, cap and rotor

My car has 141000 miles.
My car has a manual transmission.

Hi There, It sounds like you may have a couple of issues going on here. There are a number of things that can cause poor fuel mileage. A faulty camshaft position sensor is one of them. The camshaft position sensor is a magnetic sensor that monitors camshaft speed to regulate ignition timing and fuel injection timing. It gathers and sends information about the car’s camshaft speed (and as a result the position of each piston) to the car’s electronic control module. This information is received by the computer, which then uses this data to further calculate the time of ignition and the timing of fuel injection required by the engine. When this is not working properly, you may experience a drop in power, poor idling, poor fuel mileage and problems starting the vehicle.

A clogged or dirty EGR valve may also cause poor fuel mileage. The EGR valve is a small component designed to allow the flow of exhaust gases into the intake manifold in controlled amounts. As such, it’s a simple valve that closes and opens as needed. The EGR valve has one single job to do, regardless of the system configuration, type of control and number of sensors: that is, to either open and direct exhaust gases into the combustion chamber, or to close and keep them from entering. Whenever you start the engine, the valve comes alive and waits in a closed position, blocking the flow of exhaust gases. Once the engine reaches operating temperature and speed increases, the valve, either through vacuum or electronic control will gradually open, allowing burned exhaust gases to enter and combine with the air-fuel mixture inside the combustion chamber. When the EGR valve is clogged or dirty, as they are prone to, it may not function properly causing the engine idle rough, stall at idle speeds, cause the car to get poor fuel mileage, or emit a strong smell of fuel due to excess hydrocarbons which also results in failing emissions tests. I would recommend having a professional from YourMechanic come to your location to diagnose and inspect your vehicle.

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: Can't get distributor times correctly

You will need to set the crankshaft to No. 1 top dead center or TDC. There should be marks on the crank pulley that indicates where this is. If you have already done this, you may be 180 degrees out....

Q: Not getting fire, changed coil and camshaft sensor?

Your vehicle is equipped with a crankshaft position sensor. That sensor is on the primary side of the ignition circuit and consequently you should test the sensor and all wiring to the distributor to be sure it is functioning. If...

Q: Why does my dome light not work when the car is on and pressing the button on my 2012 Ford Fusion

Hello. If the dome light will not turn on with the switch then the switch itself is more than likely defective. If the light works at all other times then the light itself should be fine and there should be...

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...
How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...