I don't know if this issue exists with all S197's or just certain year models, but I own a 2007 Mustang GT and I was plagued with this problem for approximately 3 years. It got so bad, that I decided it wasn't worth it and decided to put in storage and get something else. This was in 2017. I decided to go totally opposite from the mustang and bought a 2017 Focus RS. And that car was fun for a while, but there just isn't any substitute in my opinion for V-8 power. So, this past July, I decided to pull the Mustang from storage. I had nearly 2 years to think about the car and what other possibilities could be causing the sudden stalls. I will define these stalls a little better so that one can determine whether this is what is specifically occurring with their GT. The car is heavily modded. Without going over all the mods, I will say that there is nothing that has been done to the car that would be considered "out of the box" concerning the mods. I am running a Maggie blower (1900 TVS), the motor was completely rebuilt by a local performance shop in my area that worked solely on Mustangs (although I believe they have since branched into a few other vehicles, such as some Mopar cars), and do very good work. Before I started going to them, I was using another local performance shop who also had a very good reputation and also specialized in Mustangs. My issue was simple. Anytime I would driving on a hwy, and running the car consistently for say, 1-2 hours, at 75-80mph, probably 1 out of 3 times, the car would start to run rough, and within a few seconds, it would completely shut down. I eventually got used to this and would immediately get into the right line and try to pull off asap. Whatever was happening would never pop an engine light. I was running a tune, therefore I could always check any codes with my SCT tuner. After waiting for anywhere from 15 to 30 minutes, the car would usually start up, as if nothing had happened and I would continue on my way. So, when I pulled it from storage this past July, I decided to try one last thing. And if it worked, great. If it didn't, then I had decided that I would cut my losses and sell it, fully disclosing the issue I had been having. I decided to have the Aeromotive 340 FP I was running swapped out for a FR dual FP. I also had the stock sending unit swapped out for a new one. I needed a new battery as well, but those were the main two items and I had one of the local Ford dealers do the work. After that was done, I put it through every scenario I could think of where it had given me the stalling issue, and I have not experienced a single stall or the car running rough since this was done. So, for anyone who is experiencing anything similar to this, try changing out your FP and the sending unit and see if that clears up the issue. I will say that the wiring harness to my old FP module used very thin wires. I swapped out the FPM 3 or 4 times, but that never seemed to help. With the FR dual FP, I now have 2 FPM's. And while the FPM that comes with that kit appears to be the same, the wiring harness that connects to it uses a MUCH heavier gauge of wires than what was on the original FPM. It is just my opinion that the wiring setup which was used with the Areomotive pump were so thin, that when the car was driven for a couple of hours on the hwy, the wiring became increasingly hot, reaching a point to where it was unable to pass communication back and forth between the FPM, the FP, and the sending unit, causing a complete failure between these components, which caused the ECU to shut down the car. This is just my opinion. But if this sounds familiar to anyone, I hope this info helps.