Long explanation but really need some advice. My Car started acting up when I sit in idle the car is running lean stays at 15.6 but smells like gas as if it were rich. Car also randomly jumps to 20 in air fuel ratio and the rpms drop and the car sounds like its going to stall out. Does this 4 or 5 times in the same minute then goes back to 15.6. Additionally when I accelerate at full throttle or half even it jerks or tugs back instead when the car is rolling and I go full throttle in 1st or 2nd it responds quickly and gives power till about 3.5-5k rpms then it jerks and tugs again losing power. Taking off from a stop sometimes it sounds like its choking as well then continues like normal. I am catless and have had my engine light for 4 years its the only code popping up.