I have a 2001 Chrysler 300m. My code reader read that all 4 o2 sensors were bad (only this would happen to me at 1 time) so I replaced all 4 sensors and erased the stored codes drove the car about 20 miles and the check engine light came on again and this time it reads Bank 2 Sensor 2 has no activity so my question is which one of this sensors is Bank 2 Sensor 2 and is it possibile that 1 of the 4 sensors i bought was bad they all 4 had the same part number.Thanks for anyone that can help me out David

SOURCE: O2 sensor problem

I have a 97 gmc sierra .This truck is the same as the chevy ok.Its a 350 5.7 liter 4x4 Z71.I took it to auto zone which was my first mistake.They put it the scanner and said bad O2 sensor.Ok so which one is it i said.They dont know.Well there four (4) O2 sensors in this truck i hope you know that.I had to replace all four of them before i had to take it to a real shop.It seems the fuel pump i replaced a week earlier with an auto zone fuel pump was bad.Ive changed my feul pump 4 times now and have 235000 miles on still running.You need to get your fuel pressure checked.It should be 65 psi to start it and 55 psi to run it.If the pressures are good it could be a different O2 sensor or maybe the mass air flow senor.My last option would be the fuel pressure regulator because it seems to be a waste of time and money.I would get that fuel pressue checked first.Good luck.

SOURCE: 2000 chevy silverado 1500 4.8

It could be that your knock sensor circuit is working perfectly.You may have a knock that it is reading for long periods.
Try running it disconnected, and see if there is a clatter or knock when accelerating lightly.

You could have a vacuum leak.

SOURCE: check engin light is on

if you used a diagnostic code retriever tester, the tester will take the light out, if you do not have a code tester, then disconnect the positive battery cable, for about 1 minute, then reconnect it, the light should be out , but you will have to reset your radio clock, hope that this information has helped you.

SOURCE: Code reader said MAP sensor

I have a same problem. need help