Hi-I am still trying to diagnose the above mentioned codes (the frustrating PO 300) random mis-fire. The PO302 narrowed this down I thought, but no matter what I do I still come up with the above mentioned codes, and I will list these latter. I think possibly I have narrowed down the diagnosis to a likely vacuum leak, since the CEL does not comes on not at idle but when the car is being driven. The # 2 coil has been replaced with an import direct new coil, MAF cleaned and working well, had the ignition switch check for correct operability, changed all 4 plugs w/NGK Iridium IX, valve does not seem to be bent since car runs and idles smooth after about 2 minutes, before that the car idles very rough in reverse (cold start), and some what in drive. The thermostat has been change as well as the coolant temp. Sensor. Any suggestions, or does this diagnosis have high possibilities of being right on?
have the same problem?
Saturday, June 20th, 2015 AT 10:09 AM