my lexus rx 300 1999 has a problem code p 0171 an aftar that code appear on my obd go to 30-40 km and starts misfire on 1 and 3 cilynder. maf sensor has no problem; i put new o2 sensors, also new pcv, new coins and etc... when i zerod my car by battery my car starts and not have any misfires, but after 30-40 km misfire on 1 and 3 cilynders starts again. please if someone had that problem help me :)