Hey Guys, glad to be here. This is my first post. 😁 I have a 2002 RL with 280,000 miles. I’ve owned it since 100,000 miles. Over the past couple years, it has developed a few issues, and I’m wondering if the issues are related. I’d (obviously) like to do the work myself, if possible…just not quite sure where to start. Here are the issues:

Engine starts, but reluctantly
18-19 MPG, at best (versus 24-25 I used to be able to achieve)
Engine surges when idling
Engine hesitates off the line with heavy-ish throttle (scary in traffic)

There are some engine codes:
P1456
P0132
P0401

I’m looking to sell it, and I’d like to fix these issues. I can do the work, but diagnosing is tricky for me. Any advice is greatly appreciated. Thanks!!