Dave, I just replaced a catalytic converter on my truck. I was getting bad gas mileage and everyone said the converter might be stopped up. My son in law who works on cars at a dealership said that if it glows red it ( might ) be bad. My truck has about 150,000 miles on it at that time and my poor gas mileage, after replacing the converter for $300.00 was the transmission torque converter not the catalytic converter. These thing can fool you. My $.02's worth John