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・Save up to 30%

Get a quote

What others are asking

Q: Misfiring on a 2003 Audi A4 3.0

You've got to replace the cover gasket valve that's leaking oil in the spark plugs. But that's not going to get it to run better right away. But I would change that. If it's running poorly, it's not going to...

Q: My car is bucking when I drive and then randomly stops shaking.

Hello. It does sound like there are a lot of issues going on with the vehicle. Before making such a hard decision I would really get a complete diagnostic of what is going on with the car. It may not...

Q: Rough idle, surging, and hesitation - 1998 Chevrolet Blazer

This may be related to the evaporative purge solenoid. The EVAP system prevents fuel vapors from the fuel tank from escaping into the atmosphere. The EVAP system collects and temporarily stores the fuel vapors in the charcoal canister. The charcoal...

Related articles

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...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.