Q: Airflow changes when I step on gas pedal

asked by on

When I accelerate, the airflow goes from the dash vents to the defroster. When I let off the gas, it returns to the dash vents.

The AC has a vacuum reservoir that is designed to hold a vacuum to the AC blend doors during acceleration, or low engine vacuum conditions. If this system is leaking, the system cannot hold vacuum to the AC, and will default to the defroster vent when vacuum levels drop. I recommend that you have a mechanic, like one from YourMechanic, check for broken vacuum lines, or a leaking reservoir, through an inspection of your entire AC system.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1,000 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!
  1. Home
  2. Questions
  3. Airflow changes when I step on gas pedal

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: Air conditioner not working at idle

Hi there. You can be experiencing a weak AC compressor clutch engagement. I recommend having a certified mechanic sent by YourMechanic come take a closer look at the Air conditioner issues.

Q: RPM goes high while sitting still miss firing 02 Deville I think 4.8

Hi...engine idle speed is controlled by an idle air control valve (IAC). A faulty or blown fuse in other electronically controlled systems can cause the IAC motor to malfunction, leading to a higher than normal engine idle speed. The IAC...

Q: Windows not coming down

Hello, it sounds like you have a couple of blown fuses. You should get the wire repaired for any that are broken. The wires could be shorting out against each other and the chassis. There is alway the chance that,...

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 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...
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...