I've been battling some electrical issues lately and they still seem to persist and change, looking for next steps. I installed the BOE Torque 300 tune to my '07 Exige over the winter along with the smaller SC pulley, bigger injectors, and CAI. After the install the car ran good and was issue free for just over a month. Then I started to have injector issues (one was a simple pin not seated well in the harness) and another kept throwing an Injector Circuit-Cylinder 3 code. That would go away after the car sat or cycled through a power off, usually I'd pull the SC off to inspect wiring and put it back together and it would run fine. That's when I took it to 3R Racing to look into it further, they worked with BOE and the next logical conclusion was a bad ECU (huge thanks to Phil for all the help so far). I got another ECU installed and all seemed fine again driving around a few blocks and for 1 track session. The second track session the engine cut out kind of, odd sound almost like the rev limiter and different then when injector cylinder 3 faulted. I have no CEL and no pending faults at the moment. After shutting the car down for 10 minutes, I was able to drive off the track and it seems fine but I have not pushed the car again yet. It was very windy so the sound is not great, but the first few seconds and last few seconds you can hear the engine sound I'm referring too. My data didn't seem to record so I cannot check if temp suddenly dropped or what might have happened. Has anyone heard this sound before and if so what might the issue be?