97 Accord Ex. F22B1

Mods:
2.5" catback exhaust with 421 header,
flowmaster muffler (2.5" in and 2x 2.25 out),
CAI
and f23 manifold

I think ive touched on this issue before but never started a thread on this forum. I've been trying to get it resolved for a while now. It seems like it started with the f23 im swap or at least afterward.

So I know that with the exhaust mods I'm gonna lose some low end torque but this is intermittent. When the car sits for a day and I start it up it has a nice throttle response. The car will warm up and will still feel the same, so its not that the car goes into closed loop or it runs hot. But after it has great throttle response Ill drive it again and its like the car is pulling a load. The high end power is fine. No CEL's have occurred relating to this. Thats my biggest enemy at this point.

When monitoring the ECU and sensors I did not really see anything odd except-

the intake temp in the manifold reads over 100 degrees when the temp going in is 30 or 40 this time of year. But the manifold is not that hot to the touch. I moved the sensor to the intake pipe and I got some power but didnt solve this issue. The coolant temp measured is at 205 degrees at full temp.
So the sensors I know its not are (after testing or replacing):

upstream o2
TPS
MAP
IAT

Tests/repairs ive done are:

Vacuum gauge (normal), no vacuum leaks or odd engine behavior
Exhaust leak and 're-gasketting'
Moving IAT sensor
Recalibrating TPS
EGR cleaning (thinking that causes the high IM temp)
Idle adjustment
Coolant bleeding
PCV valve replacement
oil change
Cat converter cleaning

I fought with the idle for a while after the f23 IM swap but at this point its alright except there's a delay- when the car is in neutral after revving it the idle will drop to 1000 rpm and then slowly go down to 750+/-.

I'm not sure if this would relate to that at all?
I dont wanna spend money on another IACV without a definite chance that this is the issue. Could it be opening up more when the car is accelerating allowing more unmonitored air through causing a lean condition and that would explain the delay in the idle?

Fuel system would cause more erratic behavior right?

Eventually I may have to take it to a mechanic but its the kind of issue you recognize after driving it for a day or two so I dont really know when Ill have time or money to take it to a mechanic. If you want data points, I can provide them, let me know what sensors or readings you wanna see.