Car stumbles and then stalls. Help?
 

Hi guys, hoping for a little help or direction with my current issue. I recently took my car out and about 5 min into my drive it sputtered and died. I pushed it to the side of the road and after a few minutes of trying it fired up as if nothing happened and drove the rest of the way back home. I took the car out the next night and sure enough it happened again, 5-ish minutes into my drive it sputters, a small backfire, and it stalls. This time the car did restart immediately and then ran rough for a few hundred feet as I made the u-turn back home and it again stalled. After about 1 min it fired back up and I was able to drive it back home. Now the car is a 96 and has an older flying miata turbo kit installed and uses the older miata link ecu that was installed and tuned by the previous owner. My understanding of the link is there are no engine codes as it uses the CEL as the knock sensor light. A few weeks ago after sitting in traffic for roughly 1 hour it did a similar stumble once out of the traffic and on the highway but it seemed to catch itself then continued on as normal Any thoughts on what my first course of action should be? Fuel pump? Dirty/clogged injectors? Bad coil pack? I really appreciate and and all thoughts on this.

Some possibly important facts:

140K miles on car and motor
Good compression 175-180 across all cylinders
Fresh turbo/intercooler/pipes(all within 1500 miles)
New plugs ngkr6 plugs gapped to .030
Battery will start the car but sometimes clicks a few times then turns over (weak/dying battery?)

CAS, fuel pump, crank sensor, etc.

When you're unable to restart the car, does the rpm gauge move at all when cranking?

Thats a great question and something I didn't think to check for, both times it happened I was in traffic and focusing on getting out of everyones way. What would this be an indication of?

My bad I thought miatas got an rpm signal while cranking but i verified in mine that it doesnt get any rpm signal til started. but I would check crankshaft position sensor and what sixshooter said. Sorry about that.

darn mobile site. Replied to the wrong thread.

A little update to this post in case anyone else has a similar problem. Looks like the culprit was a dying fuel pump. I was hesitant to swap it out due to the car running a bit rich and that made me assume it wasn't fuel related, however, I decided it would be worth changing to eliminate it as a possibility at the very least and sure enough the car runs great now. Car is much smoother and my AFRs are more stable. Also side note: I have a hard dog roll bar and was a bit nervous that I wouldn't be able to remove the fuel pump due to the harness bar(searched for a similar question and found no answers) but it didn't pose a problem in the end. Thanks for the help guys.