Am I really reading this correctly?

[rustytruck50]

Ok...I've been doing lots of reading here about various Quadrajet & timing issues. I have been getting what I would consider lousy mpg(4-5) and driving at highway speed seems to result in a bit of struggling to maintain 60 mph. In park, it sounds like it has a bit of a miss and doesn't run terribly smooth in gear.
I have replaced a bad fuel pump, put new cap, rotor & wires on, switched out the fuel filter& pcv valve...only because it had sat for a long time before I bought it last year.
Could I be having timing issues, collapsed fuel sock, maybe even a bad fuel pump? I've been trying to adjust the idle mixture screws because I was thought maybe I had some problems with running rich, but it really hasn't helped. It's been a while since I've worked with this stuff & I'm a but on the rusty side. So, feel free be a straight shooter---I can take it