Along with my other problems, I am in dire need of a muffler, mine looks as if it got shot with buckshot. I do not know thee history of my O2 sensor either. My truck has 188K. Trying to boost fuel milage, I am getting 14-16 and just get it running good. My check engine light is on for my O2 sensor. Should I replace muffler first, and see if that corrects my O2 sensor reading, (read where a certain amount of back pressure is needed), and with ALL the hole I know I am not getting ANY backpressure. I priced a muffler and tailpipe assembly at Advance Auto for $100. Does anyone know of a cheaper or better quality for the money source for muffler/tailpipe assemblies?

Without question replace the O2 sensor. The muffler won't help with the poor performance and bad gas mileage nearly as much as a fully functioning O2 sensor.

When you get ready for a muffler see if that shop is still open in Prattville across from the Old Larry Puckett Chevy dealership on US31. I used then in the past and they did good custom work for cheap. <img src="/forums/images/graemlins/cheers.gif" alt="" />

PS I'm assuming you're in Montgomery, Al. ??

Yes I am in MGM, AL. I was just gonna buy one, its only 2 bolts to the cat. conv with a gasket. How hard can it be?

Have you replaced the CAT? If not it needs to go as soon as you get the fuel mapping fixed.

Have not replaced the cat. One Benjamin Franklin at a time. Gonna put in the O2 tomorrow. Will keep posted.

x2

O2
CAT
Then the muffler
or both at the same time.