2001 Corvette
As for the mileage. Couple of possibilities:
1. Change your spark plug wires. Plugs should last close to 100,000 miles. But the wires are now 10 years old. Dry rot is a potential concern. Get a set of either GM performance wires, MSD, or Taylor. They are all good and should have no issues with replacing them once you get the old ones off.
2. I doubt you have an O2 sensor going bad at 37,000 miles. However, I would check all your connections and make sure they are clean and good. Again, 10 years can cause corrosion/oxidation on the contacts.
Good luck.
OP good luck with the problem solving! Let us know what you find!
Softer compound - leads to a slightly larger contact area due to more sidewall flex
Better traction
Therefore you have a higher rolling resistance due to surface contact area and softer stickier tire.
Of course, everyone has an opinion on this. But in general a new tire will get less gas mileage compared to an older, harder tire.





