Skip the auto shop - Our mechanics make house calls

Q: When the rover is cold, the idle is steady, but when it gets cold, the idle changes. I have to keep my foot on the gas and brake

asked by on

When the rover is cold, the idle is steady, but when it gets cold, the idle changes. I have to keep my foot on the gas and brake or else the Rover will die

My car has 135000 miles.
My car has an automatic transmission.

A: Hi, thanks for writing in. I’d be happy to ...

Hi, thanks for writing in. I’d be happy to help.

This is a case of an idle air control valve not working properly. An idle air control valve literally bypasses air around a closed throttle plate so the engine can get air at idle. Because it bypasses air, it’s also called an air bypass valve. On start-up, the engine control module (ECM) or powertrain control module (PCM) checks engine coolant temperature, ambient air temperature, barometric pressure (on some engines) and then determines how much air and gas is required to start the engine. The idle air control valve works at idle and during deceleration-- in other words, any time you take your foot off the pedal. During deceleration, the computers on most fuel injected vehicles perform a “fuel cut” procedure where the the fuel injectors are forced to cut fuel to the engine resulting in RPM drop. However, since the pistons are still moving up and down, the engine still needs an air supply. The idle air control valve opens during deceleration to provide that air. This appears to be the problem you are experiencing.

If you would like help resolving this idling issue, consider having an expert automotive technician from YourMechanic come to your home or office to inspect your vehicle for you, and make any repairs as needed.

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: Steering wheel grinding and vibration - 2011 Land Rover LR4

Hey there. It is possible that you have a tie rod end that may be wearing out. The steering system is under greater strain when the vehicle is stopped or at low speeds compared to when driving at higher speeds....

Q: Car has an electrical problem

The turn signal switch may have failed and caused other issues as it is tied to many circuits. The multi-function switch must be inspected and the circuits it covers to make sure there were no shorts. If the wiper pump...

Q: Was driving in D pressed the pedal car wouldn't move engine revs up but car doesn't move forward.. It's fine now

The manufacturer has a technical bulletin to cover this problem. They would first check for any standing transmission problems then reprogram the PCM power train control module to the latest levels. Get in touch with your dealer to have this...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
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...