Hello,
I have 2007 Chevrolet Aveo. I have changed spark plugs, new battery, changed and checked brake system. I still have this issue sometimes when am braking the engine loses power and at times will cut off while braking or if you brake hard it’ll lose power, the car shut down, the engine, power steering and everything went off and all the dash lights lit up. Even sometimes when on parking and AC is on, once I change gear to D or R it shuts down. And it looks like the AC is weakening engine’s power also.
I need help as it seems that those mechanics I went to are uncertain about the cause and solution.
I think your “Idle air control valve” may be have a carbon build up , and is hanging up when the engine needs a higher idle. It can be cleaned with a sensor safe cleaner.
For reference, when you apply the brakes the power brake assist uses engine vacuum and as this vacuum is needed the engine control module signals the IAC to increase the idle to keep the engine running. When the IAC cannot…the engine bogs down to where it will stall. When it stalls all the lights will come on because the ignition is on but there is no engine turning to power any of these items.
The brake booster was the first thing that came to my mind too.
The booster uses the engine’s vacuum pulling on a diaphragm to help push the rod in that applies the hydraulic pressure in eth breaking system. A vacuum leak in this system acts like (is, actually) a vacuum leak to the engine.
The way to test this is to pinch off or disconnect and plug the vacuum line at the booster and see if it affects the condition. WARNING: this will make your brakes require a lot more pressure to apply. They will work, as the hydraulics will not be affected, but you’ll have no assist. Do this test in a safe setting.
Your vehicle has an electronic throttle body, which means there’s no Idle Air Control valve that controls the idle. The idle is controlled thru the throttle body by the computer.
You can try cleaning the throttle body by using a throttle body cleaner to see if that solves the stalling issue. WARNING:DO NOT OPEN THE THROTTLE PLATE IN THE THROTTLE BODY BY HAND.
To get the throttle plate open, turn the ignition switch on and either have someone hold the gas pedal to the floor, or place something on the gas pedal to hold it to the floor. The computer will then open the throttle plate so the throttle body can be cleaned.
I’m thinking this may be a leaky brake booster, same as a few posters above. When that happens, besides allowing excess unmetered air into the engine and making it run lean, in some cases it can also allow the engine to aspirate brake fluid into the intake manifold. OP could check the brake fluid level, might provide a clue.