Ok. So I'm having an issue when applying the brake that causes my 94 Civic d15 to stumble and stall with check engine light coming on. If I let my foot of the break soon enough the car would idle normal and check engine light would go away. I originally thought it was vacume leak caused by the booster or check valve. I removed the booster vacume hose. Plugged the port on the intake manifold and problem still accured. I thought I may have had some bad bulbs in the break system so I unplugged each break and tried with the problem still there. So then I pulled the break fuse and I can press the break all day without any issues. So unfortunately i narrowed it down to a short in the break system. My question is could the brake light switch cause this. I figured that if the wires on the system shorted somewhere it would blow a fuse instead of affecting the motor. Iv read thread after thread and can't find anything similar to my issue. This is my last resort. Any help is appreciated

 

 

Yeah, I figure it the same ... if the wires on the system were shorted somewhere then it would blow a fuse.
If you pulled the brake fuse then it should mean that your brake lights do not come on when you hit the brakes.
You have effectively removed a load on the engine (through the alternator)

Still wouldn't rule out a short somewhere (if the short isn't a dead short to ground)

 

Why didn't you pull the CEL code?

Also do this:

 

this seems like a very easy fix
lets start by saying what the problem is

on all cars when you put a electric load the rpm will drop by about 100 for a second and then
the alternator will give you the volts back and the rpms will go back to normal

but!! your problem is that your rpms are too low to begin with
so when you put a load on your electric system it almost kills the motor and sometimes does
also the brake booster when the brakes are pressed it also lowers your rpms by about another 100
so your dropping about 200 rpm to low minumum

your fix for this is easy you see
1st you clean your throttle body
just the butterfly inside and see how much more air flow you get see how much rpms you gain
if its 200 more then your good and your problem should be fixed but if not then go to step 2

2nd raise the rpms useing the idle screw
remember only 200 more tops
so on your idle screw its about a 3/4 turn only
your car will act funny for a few miles
it will idle like at 1500 and then 1700 and then jump around
this is only untill your ecu figures out whats going on
then all by itself after a few days of driving it will make adjustments
the motor will idle like at 900 rpm witch is the sweet spot for honda motors

and youll be a happy driver

let me know how this goes

 

Sorry for the late reply. Has been really wet where I live haven't been able to troubleshoot. I drove the car to work today thinking I solved the problem by replacing the brake light switch. Thought that was the case because started no problem without any issues when pressing brake. Till I got to the gas station and pressed the brake and the problem returned. So therefore im thinking it has to do with the idle as stated. Is there a step by step guide to abide by when adjusting idle screw. Like jumping the blue check engine light plug so the computer can learn the new setting. Do I have to unplug iacv. Won't the iacv compensate for the idle screw adjustment. Going to try cleaning the throttle body tomorrow. Would it be better to remove and clean it. I know there's two ports in the body that have a tendency to plug. And around 900rmps at operating temperature seems a bit high is this correct

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The code that pops up when pressing the brake.is 13 witch due to my research comes up with Barometric pressure sensorDo you think the the ECU itself is malfunctioning and causing this when I'm pressing the break. Idle is fine. all is fine till I press the break... Is these a full break line diagram I'm able to obtain.

 

Replace the ECU.