I recently purchased a 04 automatic and love it. Had some trouble with the dealership who sold it to me long story short they replaced the tranny and harness. Since then it started stalling on me thought it could be the Mass Air Flow replaced it wasn't it, replaced the secondary air injection worked okay for a few minutes but then started again. Erased the codes and a U0100 and P0420 code came on. I know about the cat I'm already replacing it could this be causing my stalls when I come to a stop while I'm driving it?

 

First things to always look for, Ignition and compression. I've got this issue due to compression, I don't really drive it, but when I do. I drive in manual mode, and when coming to a stop I toss into neutral, then back to manual to drive. Just a band-aid. Get those checked and report back.

 

Search or Troubleshoot.

http://foxed.ca/rx7manual/2003mazdar..._S01_0016.html