Car stalls once in a while

Mine is 2003 Type-s Acura TL with 95k miles. I bought him with 56k and it had problems with the transmission. After the dealer changed the transmission (I don’t know if that’s related to my problem) my car has stalled about 6-8 times within 1 year period / 30k miles. It happened when I did ‘hard’ stops, like when I’m going over 45mph and I had to stop because the streetlight changed to ambar, but it was not a ‘burning rubber’ kind of stop. It does not happens always, it’s actually very few times it’s done since it started about a year ago. I used to take my car for service to the dealer but I always forgot to tell them what had happened. Any ideas?


HOW does the engine stall? Suddenly? A stumbling stall? Any loss of dash lights, radio, etc?

No stumbling, nor loss of dash light. The way it stalls, it’s when I stopped (just like a regular stop) the car stopped normally, the rpm needle went down all the way to “0” and the engine stalled. there wasn’t any vibration nor the car jumped.
I don’t know if this helps, or if you need more info.
Thanks for the help!

My first guesses would be a sluggish idle air control valve or some kind of a weird leak in the brake booster or check valve that requires some higher than normal pressure - if it has to do with those hard stops. Neither of those have anything to do with the transmission.

Thinking along the lines of the transmission the only thing I could think of would be a sluggish torque converter clutch - where it isn’t unlocking quickly enough on hard stops.

If you slow to a stop gradually and then sit at idle with your foot on the brake what happens? Nothing? Any kind of occasional stumble or shaking?

Is the check engine light on?

No, the engine light is not on.
If the car is at idle with my foot on the brake nothing happens, it doesn’t vibrate, nor shakes, nor stumbles.
Besides the fact that the car has turned off those 6-8 times the car is running very well.
I haven’t felt any problem with the transmission when it shifts gears. About a week ago I was driving on a steep incline and there was a moment I kind of over-stop and go and the transmission shifted without any problems.
Do you think this may be something a regular mechanic could figure out or it’ll be better to pay the price and take it to the dealer?

There are good mechanics at places other than the dealership. Ask around.
The lockup torque converter not unlocking is still a suspect; but, because it happens so infrequently, it’s very hard to be sure. Try a succession of hard stops from 45 mph to see if the engine will stall. If you can intentionally get it to stall, try hard stops (from 45 mph), and put the gear shift in neutral as you near the full stop. Then, if the engine doesn’t stall, it may be a faulty torque converter lockup causing the stalls at the other times.

Thank you, I will try that and I’ll get back to report what happened.

hellokit’s advice for troubleshooting is good (as usual) - I wonder though if there might be an easier way than doing the shift to neutral. Is there something like an “O/D Off” button? Or a lot of cars won’t engage the TCC if the gear shifter in 3 rather than D. You could try that. Though I admit that shifting to neutral is not such a big chore.