Skip the auto shop - Our mechanics make house calls

Q: High revving enginge

asked by on

So we just got this car out of the garage and it drove perfect all weekend (170 miles). The day after we went to visit family a plastic piece was discovered under the car. When I looked it up on fordparts.com it said it was an air duct. I've looked virtually everywhere I can and can't find where it goes. Shortly after this piece is discovered the engine started revving really high like I was flooring it. We cleaned the throttle cables (that worked for about and hour), we cleaned the throttle body (that's did nothing), we replaced the mass airflow sensor, speed sensor, nothing has changed. The gage on the air cleaner is still green. When we take the air cleaner off it doesn't Rev high.

My car has 150000 miles.
My car has a manual transmission.

A: Hello. Most of the time when this engine st...

Hello. Most of the time when this engine starts revving high all of a sudden, it is because of a vacuum leak. This can occur if any of the vacuum hoses or elbows break. I would need to see a picture of that part to know for sure where it goes. If it is indeed part of the air duct, then it can cause an incorrect reading to the mass air flow sensor which will also cause this.

One other part that will also cause this to occur is a bad throttle position sensor. If this fails and reads incorrectly, then this will occur. I usually check the computer for codes and to check fuel trims to see where the problem is. If you need to have this looked at, consider YourMechanic, as a certified technician can come to your home or office to diagnose the revving issue more thoroughly.

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: When engine is cold it makes a rattling noise when you put into gear, but when it warms up there is no noise.

Hi there. There could be a bearing failing in the engine or the power steering pump bearing could be going. First try to turn the steering wheel when the sound is present. If the noise diminishes or dies out, the...

Q: Shaking in steering wheel at 120/km

The most common reason for a vibration while driving is a tire issue. The tires may be out of balance, or just worn to the point that they will cause this. Typically, the brakes won't cause this, unless it happens...

Q: Engine rpm not steady at 40-55 mph

This is a common sign of a failing throttle position sensor. The throttle position sensor (TPS) is a sensor used to monitor the throttle position of a vehicle. The sensor is usually located on the butterfly spindle/shaft so that it...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
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...
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.