Civic hx help

[Jakins]

Ok. So my Car is feeling really week at low rpm's and the CEL comes on if I cruise below 1500 rpm. Before I registered on this site I had now clue what lean burn was. Now after researching it for several hours I am severely confused lol. One of my questions is, how do I know if I'm in lean burn mode?

This is my problem though. Bogging and poor mpg. 5 years ago I turbo charged the car and took it off, it never ran the same sense. The problem was it would idle super low and die intermittently. My dad used the idle set screw to just make it high but that was a quick fix. The motor eventually died. I swapped it out with a d16y7 (using the d16y5 distributer and ecu) and strangely it presente the exact problem. But than I replaced the head with my rebuilt d16y5 head and it still did the same thing. I tried everything. One day I cleaned out the ports and egr valve (not sure if I did the valve right because it was closed. Tips?) and I cleaned my o2 sensors with carb cleaner. I also replaced the plugs wires rotor and distributer cap. Made a minor difference. Next I swapped out the fuel pressure regulator and fuel filter. That kept it from ever dieting again but it still fluctuates and flies up to like 1500-2000 rpm some times. Last night I checked the fuel pp and found the sock to be clean. Havnt checked the fuel pressure yet. I tested my ignition coil and it was fine. In a couple hours I'll be checking my ICM. Also my timing was at like 20 lol. My fault. I moved it down to like 12 btdc witch helped a tiny bit.

What else could it be?!?!??????!!

Should I do a valve adjustment? The cel is not on. The only thing it ever throws is miss fire codes if I drive it at real low rpm's idk what else to look at.