brake = rpms dip

[p00t]

when i push down the brake during hard stopping my rpms dip alot. when i only put moderate pressure on the brake pedal it hardly effects the rpms at all, but does dip slightly.

sometimes it wont do it ... some times it will. people have mentioned that the vaccum line going from the brake booster to the throttle body would cause these symptoms if it had a leak. I have inspected the line and there are no cracks, tho that does not rule out a leak.

The brakes were possibly incorrectly installed on the car by the previous owner because the brake pedal has had a spongy feel to it since i bought it. Could the fact that the lines might not have been bled correctly which causes excessive pedal travel be the sole source of the problem?

I will inspect the vaccum line more thoroughly but i dont think it is the cause. I traced it back to the throttle body (i think). are there any devices or doodads in there that may be malfunctioning (valves, selinoids, etc)?

If i dont know WTF im talking about, please smack me in the face real hard with the facts...diagrams...presentations... whatever!

[yellow_jacket]

If the rpms are dropping under braking it is usually a leak in the brake booster. This can also be caused by other malfunctions though.