I have a 1999 lightning and it started running rough during light throttle while cruising. idle is around 1100 but will drop in the 9's if it sits still for a minute. I have both 02 sensor code(bank 2 sensor 2) and EGR p0401. truck has 120,000 on it. should I pull the tb and clean the EGR ports? I also have high flow cats that may cause the o2 sensor malfunction from what i hear.