I have got this code mostly at 20-35mph at 1200-1300 rpm. If I clear code and drive mostly highway it is fine. If I start to run lower speed roads it comes right back. So here is a list of parts replaced cap,rotor,plugs,egr and all 4 02 sencores. Befor I spend $350 on cats I wonder if timming or some thing els could be the problem.