terik.m

My sister's 90 Accord has an automatic transmission. While cruising everything is cool but when she comes to a stop and depress the brake pedal the car stumbles and dies. We replaced the fuel pump, filter and tuned the car up....the problem still occurs. Any suggestions on what to look into. I checked for vacuum leaks but did not find any. I was maybe thinking it was an internal vacuum leak in the brake booster. Keep in mind it only happens when the brake pedal is depressed.

hondadude

I would suggest you unplug the IACV and see if the idle drops.....The screen on the IACV might be all plugged up.
You could also clean out around the throttle plate with carb cleaner and a toothbrush to help improve idle.

What is the idle RPM?
The brake booster uses a large amount of available manifold vacum, so low idle or any vacum leak will cause this situation.

P_Adams

I have to agree with Hondadude on the original observation. Get yourself a can of spray carburetor cleaner and go about cleaning the Throttle Body and it's attached Idle Air Control Motor (Valve). Crud buildup from the PCV system eventually builds up and can effectively shut off the engine.

Terik.m has another point to make. The brake booster may fail, causing this condition. It will (however) be announced by an audible hiss from under the dashboard as the booster vents thru the pushrod bellows. It will also show a propensity for a hard brake pedalm and the engine often shakes when the pedal is depressed.

P