Skip the auto shop - Our mechanics make house calls

Q: The engine revs up and lurches toward, while applying brakes

asked by on

My car ran fine and had no problems. One foggy morning however, I was driving and stopped at a stop light. While pressing the brake, the engine suddenly revved up. The car lurched me toward the stop light. I took it to the dealer, but he didn't find any problem. This happened again one rainy day. The engine started revving. The car lurched me toward while I pressed the brake. What could be causing this? I appreciate your help.

A: It is possible that your brake master cylin...

It is possible that your brake master cylinder is leaking brake fluid into your power brake booster. Your power brake booster is connected to engine vacuum so if a flammable liquid such as brake fluid were to enter the power brake booster, the engine would be able to inhale that fluid.

When the excess 'fuel' is added to the engine, the powertrain control module (PCM) will increase the idle speed to compensate for this extra 'fuel'. I would recommend having this high idle speed issue diagnosed by a certified mechanic for best results.

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

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Save up to 30%

Get a quote

What others are asking

Q: I changed my battery but every morning my car is dead and I need a jump?

Hi There, It sounds like you may have a faulty alternator or voltage regulator. As you may know, the alternator is responsible for charging the battery while the engine runs by generating amperage and recharging the battery while the engine...

Q: Brake Spongy after Bleeding

There is either air still in the brake lines or potentially a bigger problem at stake like a potential vacuum leak in the brake booster. Before diving into the brake booster, I would suggest having an expert from YourMechanic come...

Q: Oil leak

Hi there. Engine oil is crucial to properly lubricate your engine's moving parts internally. An engine may seize without the proper lubrication in the system. Your oil may have leaked from your oil pan, oil filter spindle, or in some...

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...
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...