Engine low power?

Engine Performance problem
2001 Ford Taurus 6 cyl Front Wheel Drive Automatic 112K miles

My Taurus is giving me major problems. It is having problems accelerating from a stop and is constantly trying to downshift. When it does, it is taching about 3K, but loses all power. I can floor it with no change in power or RPM. On a grade it is nearly impossible to keep it going. I have to lift off the gas to get it to upshift and when I apply gas again it tries to downshift again. Even at highway speed (when I can get it to one, which isnt easy), it still tries to downshift and I have to lift again. I dont think it ever gets to overdrive, but is shifting between third and second.
A friend looked it over with me and we found the EGR solenoid broken at its mounting bolt and laying on the manifold, resulting in it being partially melted. It was replaced but no improvement. He tried reading the codes stored, but got only a low volt tosomething (I forget what exactly). I took it to a dealer to have a diagnostic run. They told me the coil pack was bad, and the mass air sensor and DPFE(?) Were reading out of spec; the DPFE probably due to a leak from the PVC valve line. I replaced the PCV valve and the line, the MAF sensor and the coil pack, but had no noticable improvement. At the friends suggestion I replaced the throttle position sensor-Still no improvement. The friend is suggesting that the computer may be defective since no codes are being sent when something is obviously wrong. Another frien suggested that the catalytic converters may be the cause.
I am at a total loss and clueless.

Yes, I do have a multimeter.
The check engine light bulb is apparently burned out, but when checked with a code reader only the lack of voltage code mentioned above was shown.

I havent done anything with the DPFE because the service writer said the out of spec reading was prolly caused by the leaky PCV hose (Thats what I was told). Therefore I replaced the hose, which came with a new PCV valve.