After routine cap and rotor I noticed the engine running rather rolling or pulsing it got worse and after an O2 sensor, fuel filter and MAP sensor failed to address things I ran dry gas, system cleaner, carb cleaner, noticed by just touching the breaks it runs great. Vacuum leak no, I found that by simply activating the break switch itself it clears the condition. Where is this switch wired to it has two plugs to it. Is it timing ECM module in distributor............what I'm at my wits end. Thank You.