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: can i get pitman arm and idler arm fixed?

Hi there. The Pitman Arm & Idler Arm are essentially the same component; however, they operate on opposite sides of the vehicle. The idler arm operates on the passenger side, while the pitman arm connects the steering box to the...

Q: Transmission fluid is leaking out and the speedometer is not working.

Many common faults will cause your 1997 Ford F-150 to have a transmission leak and a speedometer that does not function. Transmission leaks can occur in various areas but the most common are the pan gasket, output seal, sensor seals,...

Q: Q: Car will not start

If the vehicle is not restarting and there is no electrical power to the computer, then your automatic shutdown relay may be causing the problem. This relay is in the main engine relay box. If you are having a loss...

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...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the...
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...