Q: Gears engage after 05 Expedition sits for a day but gears stop engaging after short drive.

asked by on

Automatic Transmission. My check engine light came on, code P0506. I had it read at auto zone. Days later, while driving, the gears slowly stopped engaging. At first, it was taking a long time for it to increase speed and within 2 minutes it stopped moving at all. When you press gass pedal, truck only revs. Both reverse and drive. I cleaned throttle body the next day as auto zone rep recommended. It worked at first. Gears engaged. I took a short (1/4 mile) drive around neighborhood and when I came to a stop sign, the gears stopped engaging again. It sat for 2 days. I tried to drive it again. The same thing happened: it worked fine for short drive and then gears stopped engaging. What could this be? Why would it work after sitting for a while and then go out again?

My car has 200000 miles.
My car has an automatic transmission.

Hi There, Code P0506 relates to the idle air control valve, specifically that the idle speed is less than the target idle speed by 100 RPM or more. The idle air control valve monitors the air intake as it is mixed with fuel prior to being injected into the engine at low speeds and at idle. This valve is controlled by the vehicle’s computer and will adjust idle speed based upon other measurements such as engine temperature, intake air temperature and electrical system load or voltage. This is also an important function when starting the motor as it allows the motor to run and idle on it’s own once the motor fires. When you accelerate, the engine RPM increases, and as you let off the gas, the RPM slowly returns to the normal idling speed with the help of the idle air control valve making the transition from a higher RPM back down to idle speed while adjusting the air/fuel ratio constantly to allow this to happen smoothly. When the engine RPM drops below the normal range of about 750-800 RPM, this often times will cause the engine to stall indicating a dirty or faulty idle air control valve. I would recommend having an expert from YourMechanic come to your location to diagnose and inspect your vehicle.

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. Gears engage after 05 Expedition sits for a day but gears stop engaging after short drive.

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: How do I turn the rear climate control system on or off?

To turn on or turn off the rear climate control system, simply press the Rear Power button.

Q: Steering issues with my vehicle.

You may have worn or bent steering or suspension components. This could cause an excessive toe in or toe out conditions causing the front tires to fight for direction. My recommendation would be to take the vehicle to a mechanic,...

Q: Brake malfunction dynamic drive on 2005 BMW 745Li

Hello. It sounds like your 2005 BMW 745Li may have a problem with your electric/charging system or that the battery is faulty. If the electric/charging system is charging too low, it will cause the electronics to go “haywire” because the...

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...
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...