2004 Endeavor, 212,000 miles

Hi All,

New to the forum. Just purchased a 2004 Endeavor off Craigslist for $1200. Love the truck. Couple issues with it that I need help with.

#1- Check Engine light is on. Code P0431. I'm being told front Cat needs to be replaced. We tried using a spacer on the sensor for now to pass emissions, but check engine light came back on. Anyone change their own CAT before? The part is like $250 on Ebay and it looks like a direct fit.

#2- The most important. When you start the car up and put the car in D or R (drive and reverse), you can hear a scraping/grinding noise. The noise gets lower and lower as you begin to drive and the car warms up. I only hear it when I'm stopped at a red light or something. When you step on the gas and drive, the noise goes away. No tranny issues. The car shifts and rides smooth. Thoughts?

Thanks