Hey guys, Derrick here. I typically don't post but, rather spend my time lurking and gathering info. Anyway I come to you guys with a problem that I haven't been able to figure out thus far. I have a 2012 F4 RR Corsacorta that's running like shit below 4500 rpms. The only engine mods at the moment are exhaust flapper valve disconnected and Bodis slip-on. Below 4500 rpms it backfires pops and sputters and idles really low. Feels like its misfiring or running on less than 4 cylinders lol. Above 4500 it feels like the shower injectors kick in or something and the bike rips. I did some research on this forum and found a few really old posts that i'm not convinced relate to my F4. To date I've ruled out the ECU, bad fuel, fuel pump, fuel filter, fuel lines and the fuel injectors and fuel rail as well. I'm fortunate enough to have a second working track F4. So I swapped these working items to my street F4 and it ran just as poorly. Last night I pulled the plugs and inspected them and all look normal. Meaning, they don't look wet or fouled. Regardless I'm going to replace them with fresh plugs this evening. However, if it runs the same that would only leave coils and or the TPS correct? Any ideas would be greatly appreciated. Thx guys!