99 yukon cel on for both o2 sensors on same side

[sirwilly]

i HAVE A 99 YUKON THAT RANDOMLY MISFIRES EVERY NOW AND AGAIN. THE CHECK ENGINE LIGHT CAME ON FINALLY AND SHOWS FAULTY 02 SENSOR BANK 1 SENSOR 1 AND BANK 1 SENSOR 2 I FIND IT HARD TO BELIEVE THAT BOTH SENSORS BEFOR AND AFTER CAT ON SAME SIDE WOULD GO OUT AT THE SAME TIME. i RECENTLY REPLACED INTAKE GASKETS WITH UPGRADED DESIGN AT THE SAME TIME I REPLACED ALL SPARK PLUGS, CAP AND ROTOR ANY THOUGHTS ON WHAT THIS COULD BE? I WAS THINKING MAYBE COIL.

 

[SunlitComet]

If misfire history shows all misfires happen on the same bank then the codes may be the results of responding to the misfires. You need to get on a scanner to monitor the sensors and read the misfires history. if all of them come from the same bank and compression is fine you may be running in to a damaged converter.

 

[Freedom Motorsports]

You can also have the converters checked at a muffler shop for flow to make sure they aren't bad, pretty simple and cheap test overall...

 

[Cyngine Smythe]

I also experienced a readout of faulty sensors 1 & 2

My engine also has a rough idle, and I also experienced a readout of faulty sensors of both 1 & 2, but after I used a Mass Air Flow Cleaning Spray on the MAF Sensor, the readout only showed that Sensor 1 needed to be replaced. Which I am in the process of ordering online now. I have read that some people say to go with certain brands. Anyone know how the "Bosch" brand works? I have a 99 Chevy Tahoe 5.7 LT 2 door 4x4

 

[SunlitComet]

Airwolf fan are you? Use delco or delphi brand only.