Changed o2 sensor and trouble code p1131 keep coming up

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: Possible o2 sensor 2002 GMC Onvoy

O2 sensors indicate unburned oxygen in the exhaust sysytem. Bad O2 sensors causes fuel mixture to run rich. It causes fuel consumption and your emmissions test will not pass. Check for vacuum leaks check the manifold.check for a misfiring cylinder, a burned exhaust valve that is leaking compression. replace the O2 sensor or sensors. Some cars have 2 . One for the intake another for the out take. If it reads a code for the Map sensor along with the O2. It is better ifyou replace both sensors. But I think that the problem lies in the oxygen sensor or sensors. Pleae vote my answer if this helps.

SOURCE: dtc codes p0155 & p0051

I had the same problem and found out I was sold the wrong sensor, my 4.0 has four, they are all different, when you install a new sensor, you must make sure you clear the trouble code before you start the engine, ignition on engine off, that should do it, it worked for me, also if you have your own scanner and can erase the codes yourself, the wrong 02 sensor will turn engine light on with cold start, then after I erased the code it would stay off all day until the next cold start, thats when I found out my new 02 sensor was for bank 1 sensor 2, and not bank 2 sensor 1, hope this helps

SOURCE: a p0340 trouble code and i changed the cam

Code P0340 is a camshaft position sensor CIRCUIT fault. This means it can be a bad sensor, wiring fault (loose connector, short, open), or even a bad PCM. Since you've already changed the camshaft position sensor you've eliminated that possibility. It's time to do some electrical troubleshooting. That, of course, depends upon your skill set for this type of work and equipment (mostly a good dmm and schematics). If you're not equipped for this then you'll likely have to seek assistance from a local shop.

If this reply answers your question then please take a moment to rate this post. - Thanks.

SOURCE: I Had a p1131 code replaced o2 sensor before cat

vacuum leak in PVC line or clogged PVC. its a leak after the map sensor. o2 sensor is correcting for a lean condition so its adding fuel to your car when the o2 sensor detects the extra air.