Reading plugs in EFI engines isn't much help. The EFI runs lean in every mode to keep down emissions except full power. Make a full power run, slow down to pull over to the side of the road to read the plugs. When you do that, the computer trims back fuel to the 14.7:1 or leaner A/F point. Now the plugs show the results of the 14.7:1 or leaner A/F that the engine was running just before you shut it off at roadside.
The only way to get any useful reading is to turn off the ignition while at full power, put the trans in neutral and coast to the side of the road. Even then you may not get any useful information from trying to read the plugs.
Reading plugs in EFI engines isn't much help. The EFI runs lean in every mode to keep down emissions except full power. Make a full power run, slow down to pull over to the side of the road to read the plugs. When you do that, the computer trims back fuel to the 14.7:1 or leaner A/F point. Now the plugs show the results of the 14.7:1 or leaner A/F that the engine was running just before you shut it off at roadside.
The only way to get any useful reading is to turn off the ignition while at full power, put the trans in neutral and coast to the side of the road. Even then you may not get any useful information from trying to read the plugs.
I disagree- espcially if you have a power adder, it is very important to read the plugs. You can detect detonation, fouling, and other issues. If you see any speckling, see it is whitewashed, or worse, then that can help diagnose problems.