I always thought I had a leak in the exhaust some where, I thought it was under the truck. Monday after having the tires rotated and balanced I took the truck to a exhaust shop for a free inspection, the guy said it was leaking from the drivers side exhaust manifld but he couldn't tell if it was the gasket or the manifold was cracked, I said it was probably a broken stud as we all know that is a common failure.   Anyway I was thinking since the O2 sensor is after the exhaust leak could the lea