Lack of power and poor fuel consumption

Crown Victoria LX'93 4, 6L (286 (?) Cid), mileage near 92000.

Done: fuel pressure checked (ok), injectors clean and Ok, adequate compression, catalytic convertor seems to work fine, MAF sensor outputs 0, 5-1V at idle (good, according to rep. Manual).

Known Faults: little white smoke, PCM outputs "EGR solenoid is high" (though the pass from the valve to intake manifold is blocked), oxygen sensors almost dead.

My problem:
The car has virtually lost much of power in last half of a year. It doesn't accelerate well though max. Speed still reaches 100 mph. When the pedal is depressed the car hesitates and then accelerates slowly. Sometimes surges while driving and has backfire with fast throttle inputs. Just like a gunshot in airbox.
Idle is rough when engine is cold. When engine warms up, no problems with idle.
The co-responding problem (methinks) is poor fuel economy. Maybe 9 or 10 mpg city and highway mixed. The same driving style brought 14 mpg city last year.

What is it? Help, please!
I'm 4000 miles away from any Ford-qualified mechanic so "find a Ford dealer" answer would not help me :)