Rough Idle and loss of power

Hello everyone. There are a lot of topics about rough/erratic idle.
Well, I have the same problem. Sometimes it will give the random misfire code. Got the P1166 code and there is also a "too lean" code. Tried all suggestions in other threads.

Believe it or not it has 34,000 miles. Bough it from my step sister and I am certain that is the original mileage since she barely used it.
Here is what I have done so far:

Replaced:

1. Fuel filter (fuel pressure reads 47psi)
2. O2 sensors (both)
3. IAC valve
4. TPS sensor
5. Intake manifold gasket
6. Throttle body gasket
7. Four injectors filters and seals
8. Timing belt (triple checked sprockets timing).
9. Ignition Coils
10. Spark plugs
11. Spark plugs wires
12. Air Filter
13. PCV valve
14. Engine Oil
15. Oil filter
16. New battery

Also cleaned:

1. Throttle body
2. MAF
3. Camshaft sensor
4. Crankshaft sensor
5. All ground contacts

Checked:

1. All vacuum hoses(removed all and cleaned them and inspected them)
2. Purge valve (it seems to be working)
3. Reset ECU by removing negative battery terminal for several minutes
4. No physical damage to intake manifold

Other info:

1. Manifold absolute pressure at idle 10inhg
2. Fuel trim 34.8% (too high)
3. RPMs from 550 to 900 fluctuating at idle.
4. Engine does not smoke
5. Good exhaust (not plugged converter)
6. Check Engine light ON

Absolutely ran out of ideas. I do not want to get rid of it. It is in excellent body condition, great suspension and transmission runs like new.

please, help.