Q: Why does my 2012 nissan altima Rev while engine is cold? It just started doing this with cold weather.

asked by on

I noticed ever since the cold weather hit, just the other day the car started reving up and down like I was stepping on the gas. Then when the car was warmed it stopped.

My car has 68200 miles.
My car has an automatic transmission.

Modern vehicles have what we sometimes refer to as a "warm up program". The transmission will hold engine revs a bit higher until the engine warms up. This is to warm up the engine and catalytic converters faster for emissions reasons. When the engine is cold, it needs more fuel to run, causing more emissions out of the tail pipe. Warming it up faster, reduces the length of time this happens. However, if the revs are surging up and down on its own, other factors may be at play. For example, there may be a vacuum leak in the intake system allowing more air into the engine. This can cause a lean condition which is not ideal when the engine is cold. Running lean can cause sensors like the throttle position or idle air, to "hunt" for the correct idle speed and give you a surging idle.

Other components like the coolant temperature or ambient air/barometric pressure sensors can be at fault. If these or any other sensor are registering improper values during cold running, the engine control unit may hunt and surge for the proper idle speed, whether you are at a standstill or coasting with your foot off the gas pedal. A certified technician can scan the system for faults as well as proper sensor values and input to determine why the idle is surging.

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. Why does my 2012 nissan altima Rev while engine is cold? It just started doing this with cold weather.

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 jump start the battery in a 2012 Nissan Altima?

A dead battery is one of the worst nightmares for drivers. You turn the key (or press the start button in this case) and nothing happens. You’ll need to jump the battery off to get back on the road. Here’s...

Q: Car will not pick up until easing off the gas pedal, Infiniti G25

Instead of using a conventional mechanical throttle, your vehicle uses a "drive-by-wire" system. This design, throttle position, and accelerator pedal position are relayed to the control module via dedicated sensors. The control module then uses this information to control a...

Q: My car overheated i believe and was jerky

Hello. It sounds like you have a serious overheating issue. If the engine is losing coolant this fast then there is a serious issue. I usually check the cooling system for any eternal leaks first and if the issue is...

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...
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...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.