My msp has been sputtering bad recently. It started a few months ago and wasn't to bad. The car was stock. After I did some bolt ons (catless exhaust, Sri intake, and ic pipes) it became unbearable. It stumbles starting at about 3500-4000 rpms and continues. I've been frantically searching for answers. Last night I reset the ecu and took it for a drive and it didn't sputter or stumble at all. Today I took it out again and it started doing it again. I am assuming I need a tune but I'm not sure. Any help is appreciated.