I was having an issue with the car running like it was on 7 cylinders. I checked codes, nothing but the required 11. I pulled plugs and they were perfect. I cleaned injectors thinking it was a clogged one. Well, long story short, one of the techs at the company I work for, (large vehicles) said try looking at the mass air meter or TPS. Turns out the TPS was sporadically grounding itself and causing that bucking feeling. New TPS and it feels like a new car. I was NOT getting a code for a bad one, just the drivability issues. I did notice that the grd wire was pulled away from the housing but still connected. Just wanted to enlighten anyone who may be having these issues.