Q: Car shakes while in idle and doesn't want to accelerate

asked by on

My spark plugs look wet but its not oil just left the shop they said my head gasket is ok... Do you think the spark plugs are wet from me keep trying to start my car ? What will cause the car to have problems starting and shaking while in idle and less acceleration

My car has 100000 miles.
My car has an automatic transmission.

The spark plugs are wet from trying to start the vehicle which is a good sign because this means that the motor is getting fuel. When the motor struggles to idle, this is generally a result of things like low fuel pressure or a dirty or faulty idle air control valve. The idle air control valve reads the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. As this valve is controlled by the vehicle’s computer, it will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed. When the engine RPM drops below the normal range of 750-800 RPM (for most cars), this often times will cause the engine to stall indicating a dirty or faulty idle air control valve. There is a brief transition period between idle and acceleration in which the idle air control valve no longer functions as it’s purpose is to regulate idle speeds and deceleration. The struggle to accelerate may suggest other fuel delivery issues such as dirty or faulty fuel injectors. I would recommend having an expert from YourMechanic come to your location to diagnose and repair your idle air control valve.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Car shakes while in idle and doesn't want to accelerate

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: Oxygen sensor bank 1 sensor 1

Hi there. Getting to the O2 sensors are tricky without removing some additional components or using specialty tools. You might want to have a professional mobile mechanic come to your location and complete an O2 sensor replacement to help you....

Q: Q: Car not starting

Hi there: It's very possible that during your intake manifold swap out that the crankshaft position sensor may have been damaged or incorrectly reinstalled; as I believe that needs to be removed in order to replace the intake manifold on...

Q: Car tilting after going over curb and impacting tree at 10 mph. Bumper bar is damaged, bumper arm broken. Side of impact is higher

The frame and/or suspension components have been damaged. To determine which will require some measurements and inspection. If all the damage is suspension related, that is assuming none of the sub-frame is damaged or the suspension mounting bosses, it is...

Related articles

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...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...