2003 civic lx automatic....as I pulled up to a stoplight and applied the brakes, the eng kept revving higher the harder i pressed the brake. and the brake pedal went to the floor?!?!?!?I already checked to make sure the floor mat wasn't hung up on the gas pedal.any ideas??

 

Check the fluid level. My first thought is that the check valve needs to be replaced. I am sure other members with more information will chime in soon.

 

It's a problem with the booster. Usually though the pedal will be harder than normal to press because there's no power boost. The master cylinder could be leaking as well leading to booster failure.

 

so if the brake booster were bad...why would this cause the excessive eng revving?? vacuum related??it's all greek to me.

 

Yes, a bad brake booster becomes a severe vacuum leak when the brake pedal is pressed.

 

thanks,we'll give the booster a try.

 

problem solved......decided to hose the throttle body down just to make sure nothing was sticking...found that a mouse or rat had come through the air intake chewed through the air filter and had proceeded to build a nest in the throttle body throat.cleaned it all out and replaced the master cylinder.all good now.

thanks to all for the suggestions