Rough Idle...
 

I have an '01 1500 5.2. It runs great, with one exception. If it sits for a day or so, (over 24 hours) I have noticed it will run at start up for a few minutes with a rough idle, then the idle levels out and it idles fine. Only once, has it back backfired at start up, at that time, it g as d sat for about a week.The computer is not setting any codes, so the computer is not helping me with the issue. I have not done a tune up, but plan to soon, changing cap/rotor, plugs, wires, air and fuel filter. I was wondering if it could be the IAC Valve or the AAT Sensor..? Anyone have any suggestions..?

Yup, start with the IAC. Clean it and the mating part in the TB.

Fuel filter isn't exactly user serviceable either..... it's part of the fuel pump module, and generally gets changed when you need a new pump.

I do have issues with the fuel gauge fluctuating, once I have less than 1/2 a tank of fuel. I have a new fuel pump, but haven't had time to install it.