This is for a Cadillac Technician. What I have is a typical Northstar mess. I have codes PO131, & PO151; low O2 Sensor voltage at both banks. I also have codes PO171, & PO174; system too lean, both banks. I also have a code PO300; random cylinder misfire. I have installed new plugs, and cleaned the MAF Sensor, and changed the air filter. This was an improvement, but the problems persist. It has a bad miss when cold, but this (seems to) clear after it reaches operating temperature. I have looked for vacuum leaks, and replaced the PCV Valve, and it's Grommet. This did little. I understand that the O2 Sensors go bad eventually, and they are a regular maintenance item. I have the 2 sensors that go on the exhaust manifolds, but I can't get to them to change them.
Would worn-out O2 sensors cause the engine to run so badly? It does seem to run fairly well on the highway, but it displays a lack of power on hills and stiff headwinds, and it seems to be getting bad mileage; about 20ish instead of the 24ish it used to get.
I want to change the O2 sensors, since I have the new ones; is there an easy way to get to them to replace them?
Thanks in advance!
Jeffrey
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Monday, March 14th, 2016 AT 5:09 PM
