A failure in this is due to excessively high combustion temps. So low octane fuel ignites quicker, car runs leaner, leaner means higher combustion temps.
So 104 (vs 87 in the tank, right now) octane gas should help, right?
To fail on all 3 measured areas leans toward cats not at their required operating temps, or cats that are tired.
Agree, but.....
They should not have failed from just sitting in the garage.
I can see that when cats begin to age, the emission numbers will gradually begin to rise. But to jump by a factor of 2x to 4x is not within the normal catalyst degradation.
Measure the temp of the exhaust before and after the cats with a optical thermometer.
What temperature should we be looking for? By the way, the car is supercharged with 8 PSI at redline. However, the fact that it has forced induction, per se, is irrelevant because the emission test is such that the engine intake is under vacuum.
