eghatch15

I have been working on my wifes 2002 is300 check engine light for 2 years. I have done timing belt, plugs wires, cleaned the MAF, checked for vacume leaks, etc. I replaced the bank 1 sensor 2 o2 sensor. Im lost and cannot figure this out. I need to get the car inspected this month. The only aftermarket parts are a header with o2 spacers and a no name short ram intake. I would put the stock air box back on but dont have it. I did the header because of a p0420. That was after the misfire codes. At times the misfire will carry over to all 6 cylinders. PLEASE HELP!!!!!!!!!!

eghatch15

Also I have never felt a mis in the car at all... It runs great