NFRS2kSi

this question is regarding audi... i'm thinking it's pretty much same stuff w/ honda..

when the brake is pressed, the RPM drops very quick and at the idle, RPM goes up & down.. it's not steady, but rather intermittent idle....

i have yet inspect the car. before i start tear the engine a part, i need some ideas.

i'll check on the spark plug & ignition coil...

milkbubble

Sounds to me like you have a vacuum leak.. And since its influenced when you hit the brake pedal, Id check the vac booster on the firewall while inspecting under the hood. Also inspect your vac hoses for dry rotting, cracks and the usual gremlins.

Stratocaster

Also a bad Idle Control Valve will do this. I am not sure if the one I swapped out leaked or was electically bad. I think it leaked.

crackaonrice

These problems are usually caused by vac. issues like previously stated (check the break booster)...but can also be caused by a faulty coolant temperature that is misinforming the ecu. The vacuum leak could be a PITA to find...something i would recommend is getting some carb cleaner or something and strategically spraying areas of vacuum hose or gaskets, listening to the motor and/or watching the tach to pinpoint the location of the problem.

blackout

If it happens when the brakes are applied definitely check the air lines going to and from the brake booster. Seems to me that this would be your culprite. You are stating the same symptoms that my old car had when my mechanic sliced my brake booster line. It should also stall out if you turn the AC on

Slows2k

Moving to Car talk. Not a S2000