Cleaning/checking grounds
I upgraded my car to a 4-wire O2 sensor a few weeks ago, which required tapping in to 2 of the car's ground points. Yesterday, I started noticing erratic O2 sensor reading on my Air/Fuel gauge. I checked to see if the ECU was throwing any codes, figuring that if the ECU was happy, the problem would be with the gauge. The ECU was actually throwing a 3, which is engine ground. So how do I go about checking the ground points and cleaning them up? Anything I can look for? Do I just need to rough them up with a wire brush? Should I put some of that dialectic goop on them?