Engine Stalling When Applying Brakes

I have a 2003 Toyota Tacoma PreRunner 2.7L 4cyl auto. This just recently started happening, but at totally random times (can’t create it consistently) when I apply my brakes, my engine totally stalls. I can leave it running for minutes and minutes, then I take it out and drive it, step on the brakes and it’ll just randomly shut off (power is still on thanks to the battery.) I replaced my MAF, cleaned the throttle body, replaced the IAC, replaced the EGR vacuum solenoid (the throttle body and IAC were throwing codes, hence why I cleaned the throttle body and replaced the IAC. Those lights shut off but it’ll still stall randomly ONLY when brakes are applied. I got a smoke machine and ran it through the different tubes, didn’t see any smoke escaping. I’m so bewildered. Going to replace the brake booster tomorrow as some said that may be the issue.

 

Idle speed? Does it do it in neutral? (ive seen converters lock and stall engines)

 

Depends, anywhere from 650-800, I forgot exactly what it was, I can check tomorrow. It has been idling a little higher since I cleaned the throttle body, tried resetting the computer (undoing the battery) as well as another trick but it still idled high. I haven’t tried doing it in neutral only because it’s totally random and typically when I’m in motion

 

I'm wondering if your brake booster is going bad, causing a huge vacuum leak when applying the brakes.

 

Ebay chinesium IAC?
Have seen alot of out of the box failures.

 

The IAC definitely wasn’t OEM, but the error code did go away that pertained to it. Doesn’t necessarily mean it fixed the stalling issue, but the code was gone.

 

You should test the brake booster either with a vacuum pump or a test procedure you can find online. They do wear out after a while.

 

I replaced part with AM fleabay, original code fixed, then new codes/issues started

So + 1 for OE IAC

Another easy thing to check is the check valve on the booster
One way valve
If failing could cause symptoms your experiencing

 

This is 96 2rz

I have seen this check valve be incorporated in that vacuum hose to the intake manifold
Unsure on a 2003
GL

 

I just replaced the whole brake booster tonight, drove it around a few blocks, nothing yet. Fingers crossed it stays this way