Skip the auto shop - Our mechanics make house calls

Q: When giving gas car will misfire and shake badly

asked by on

Some days when I go to leave in the morning crank the car and idles with no problem runs smooth. When I pull out, the is a very small incline and acceleration to speed up the car misses badly and will barely make the hill and continue to shake. No lights come on for a warning. I have driven on to the shop only to be able to reach 15mph max and had it towed 3 times. Each time when getting to the shop it runs perfect and will continue running good a day or two and do it again. They have changed fuel filter, fuel injectors (which it showed on the test once), catalytic converter, and a couple of sensors and can't locate the problem. Please help if you can. Thanks

A: Unfortunately, that seems to always be the ...

Unfortunately, that seems to always be the way things go. The problems act up when not at the shop and then vanish when the mechanic is looking at it. From what you describe, this may be a sign of a dirty or failing mass airflow sensor. The mass airflow 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 fails, this can cause 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 is what causes the hesitation or loss of power you describe. This can also cause the engine to struggle to idle for the same reason. To avoid any unnecessary repairs, I would suggest having a professional from YourMechanic come to your home to diagnose the shaking condition firsthand and service your mass airflow sensor as necessary.

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: very low power in 2nd gear engine knocking noise

If the knocking noise happens while you feel like the vehicle is chugging, this could be a misfire. Misfires are ore likely to happen when the engine is under a load, like during acceleration. Usually a misfire will cause the...

Q: Engine shimming problem

Hi. When the engine shims or shakes there could be multiple things causing this problem. The most common cause is the spark plugs and spark wires are bad and causing the car to misfire. A misfiring engine will cause the...

Q: Auto transmission is not going into overdrive.

Hi there. The transmission may have burnt clutches in the overdrive clutch pack. The solenoids for this transmission would not go out without effecting more gears. Check the fluid to the transmission and see if it is dark red or...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
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...
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.