how to stall an automatic car

Short answer: you don’t, and you shouldn’t. Automatics use a torque converter (or CVT) to keep the engine spinning happily, so deliberate stalling isn’t really a thing. If an auto does stall, it usually points to a fault—think failing torque converter, grubby throttle body/idle control, weak fuel pump, or a sulking crank/cam sensor. Trying to force a stall (neutral drops, slamming into reverse, or brake-standing in gear) is dangerous, expensive, and a terrific way to fund your mechanic’s next holiday.

If your car cuts out at stops, get it diagnosed: scan for codes, check idle settings and transmission fluid condition/level, and fix the underlying issue. Save the stalling practice for a manual in an empty car park—your automatic would rather not play crash test dummy today.