I have a 2007 m8 That backfires all the time at high rpm. I have changed the stater and pick up coils,I have went over every inch of wiring, I have changed out the throttle bodies,tps and injectors. I have also disconnected the tss and the oil sensor thinking that the ecu went in to limp mode, there are no codes flashing on the dash. The sled runs great at low to med rpm but when you go to full throttle it starts to back fire until you let off the throttle and return to half throttle which led me to believe it was in limp mode. I live at 5000 feet and ride at 7 to 10,000 feet and it does the same thing no matter where I am at. I don't know if I could have a fuel pressure problem and haven't checked that yet but it seemed more electrical, There is plenty of fuel returning to the tank when running. I am running 88 non ethanol and amsoil. Plugs do not look lean at this point. I have disconnected the wiring to the hood and get the same thing. Now I am lost. Thanks for the help in advance.