Hi,

The problem is for a 2003 Mazda3---about 50,000 km. I had the CEL go on a few weeks back. Brought it to Autozone and it read:
I was advised to check to see if my gas cap had been tightly capped, then to disconnect and reconnect the battery to clear the CEL, and to see if it re-lit (indicating that it was indeed, a serious problem and not a glitch).

I did so, disconnecting and reconnecting the battery. The CEL went off and has stayed off now for a few rides. I also did the idle relearn process, leaving the car in Drive with the parking brake on for 10 minutes, then 5 minutes.

However, the car (still) stalls when I decelerate (braking), usually from 4th or 3rd. The car seems to decelerate fine from 2nd to 1st, or if I'm just letting go of the gas. The idle used to be rough (on the first ride), but now it's quite smooth. Apart from this stalling issue, which occurs upon quick decelerations, the car seems fine. The CEL has stayed off.

What do you all recommend? Is this simply part of the relearning?

 

I wondering if you may simple check all your vacuum hoses. It sounds like a vacuum leak problem.