Where is o2 sensor on 2000 silverado - 1998 Mercury Grand Marquis

Check engine light on ? Code's ? Scan data from a scan tool , MAF - mass air flow sensor , map , fuel trims , O2 sensor etc....

Id have to check the o2 sensors on datastream with scanner, depending on o2 sensor data and short term fuel trim, could be either an o2 sensor bad or the catalytic converter bad, you might also check the fuel filter, if your lucky

Generally you have an O2 sensor in front of and after each catalytic converter in the exhaust system.

Did you change all the O2 sensors on the Catalytic Converter?

A code P0137 may mean that one or more of the following has happened:

• Faulty o2 sensor Exhaust leak near the rear sensor
• Plugged catalyst
• Short to voltage on O2 signal circuit
• High resistance or open on O2 signal circuit
• solutions are
• Replace faulty sensor
• Repair exhaust leak near the rear sensor
• Check for restriction in catalyst and replace as necessary
• Repair short, open, or high resistance on o2 signal circuit

It's inline in the exhaust system. You'll see one on each bank of the engine before the catalytic converter and one or two behind the converter. It's fairly easy to change, get your hands on an O2 sensor socket and get an OEM GM replacement sensor, don't cheap out or you'll be asking for trouble.

Did you disconnect the battery for 10 minutes or use a code reader to reset the light? My 2000 has 3 different o2 sensors and could easily replace the wrong one you usually dont know

Try the mass air flow sensor had same problem and replaced all o2 sensors, did not fix. Took to shop they changed mass air flow sensor runs good now.

Either replace the O2 sensors, or put a black piece of electrical tape over the check engine light.

you have to know what the code is that your truck putting out your truck has 4 O2 sensors. the trucks computer is smart and the code will tell you witch one is bad but if you replace just one the next one on the same exhaust pipe will probley go bad so its safe to replace all four. the draw back to replaceing all of them is thay cost about 80 bucks for one ACDelco O2 sensor. It has to be done before it will pass Emissions. not a hard part to change about a 7/8 open end wrench will take it off. have fun.