Hey everyone! First time ever posting on here. So I have a 2006 sti 34,000 miles on it and it has a good bit of mods done to it. Bought it from the dealership like it is and they wouldn't let me contact who traded it in to see what all he had done so I don't know if a mod is relevant to my problem. I'll list as many details as possible about what's going on. When I get into near peak boost it will sputter almost as if it isn't getting any fuel. When I start the car it will sometimes fluctuate between 500 and 750 rpms. My air to fuel gauge will sit between 14.6 and 15.2 but usually at 14.8. My cel light would come on when I got on it a while back for a cylinder 4 missfire, then more recently I got cylinder 1 missfire. I checked the maf to see if it was dirty and was clean as a whistle. I was also getting gas on the base I'm stationed at which has 15% ethanol and I learned that was bad so I ran a battle of Lucas oil fuel injector cleaner through it and started using 91 octane 100% gas. It's the best in town unfortunately. Haven't had any cel light but the sputter still exists. Also tonight I was running it and I had the sputter and my cel flashed at me for about 10 seconds and then went off. I also have a v1 accessport (came with car, upgrading next week) and the tune it's using is 20g low, I'm assuming it's a protune. It also has 20g high on it as well. I hope what I listed was adequate to get an idea what's wrong. Any help would be greatly appreciated!