So I have an Atomic system on the car for about a year now. It was a used earlier version I got from a buddy that did a LSx swap. I uploaded current EFI software on it. I was running it without timing control and felt that it was time to add to it. I had a MSD distributor, 6AL and blaster coil on the shelf from another project, so I did the switch. After some trial & error I got it to work very well. What a difference! Car pulls way harder off the line and will drop to a smooth idle without hunting.
So went out for a drive last night and after a smooth hard pull, it didn't drop to a smooth idle it stayed up a little higher and was rough. After about 10 seconds it settled back down. Went to take off and was rough on acceleration and backfired through the exhaust and never cleaned up. I headed for home. Pulled up to the next light and it idled smooth. Left the light clean pulling hard and no issues. It did this intermittently back & forth till I got home. At home went through the system and found nothing unusual readings were right on and there were no errors. I'm assuming that if the problem is with the 6AL or the coil it would not show up on the handheld? Any suggestions are welcome. Chevy 383, pump in-tank with return line.