Muffler vs. Fuel Economy

Can a hole in a muffler, even if it’s small, affect fuel economy? I notice a loud noise at cruising speed at acceleration.

Vehicle: 1986 Lincoln Town Car

Not likely. Why? Are you getting phenomenal mileage while the exhaust is leaking?

The Lincoln’s mileage is almost 184K miles & the muffler was replaced once since the car was purchased brand new (the car has a dual muffler). If it isn’t taken care of, will it not pass smog?

It will not pass emissions inspection if there is a hole in the exhaust.

A hole in the exhaust after the catalytic converter will not adversely affect gas mileage, and is unlikely to beneficially affect gas mileage unless the old muffler was disintegrating and had become plugged with rusty metal chips (unlikely)

If you’re about to sell the car, get a muffler repair kit (patch) from the auto parts store. If you want to keep it, spring for a new muffler. No reason to drive around in a ‘heap’.