My check engine light came on so I hooked up an OBDII scanner ELM327 using EasyOBDII software. Says misfire on cylinder 5 and 6. I decided to check my o2 censors. Bank 1 sensor 1 and Bank 2 sensor 1 voltage working fine. But sensor 2 on both sides read 0.000v during the entire test. The average RPM was about 750. I also noticed that every so often I would get a checksum error data corruption. This would happen after about 45 seconds to 2 min didnt really time it just guessing.

I am going to change out the 2 misfiring plugs tonight once the engine cools a bit but I am more concerned with the 2 sensors reading 0.000v and the data corruption errors. As the title says I believe it to be a bad ECU but figured you guys may have another suggestion that was easier to fix or cheaper or more likely.

My truck is a 98 F150 4x4 5.4L V8 extended cab with 160k miles, gotts mod

 

Was the truck up to operating temperature? Not sure if that year has heated oxygen sensors or not. If the vehicle wasnt up to temp the sensors would be operating porperly. At operating temp the sensors should jump from .5v to 1.5v, IF the sensor is working properly.

The only way to be sure is to probe the wires at the 02 sensors. Without a schematic in front of me: Its probably a 3 wire sensor, Black will be ground, white will be 12v signal, and grey will be 5 volt reference. (It may be a 4 wire which would have a second ground for the heater circuit. You may be loseing one or more of these references. If you have all of these, and still no results then your 02 is crap. If you are missing one then you need probe at the ECM and figure out if the computer isnt sending the signal of you have bad wiring.


Now mind you, Im just guesing without any diagram in front of me.