rough running mini van

We are working on a '96 Windstar that is running rough and has NO power. Pressing on the gas pedal yields poor throttle response and an acceleration that can be measured in glacial time periods. At first we suspected a plugged cat, but when we pulled the O2 sensor to investigate we found the cat completely hollow! (that's a completely separate issue I'm curious about). Regardless, we then turned our attention to the EGR system, so we pulled the intake manifolds (upper and lower), THOROUGHLY cleaned the lower (4 out of 6 EGR passages were plugged with carbon), the gaskets WERE shot, reassembled, flushed the cooling system and have no change. We've tried a new PCM (junkyard), no change. Still backfires and has no power. It has good spark on front three cylinders (13-18kV with 1-5ms burn time), computer does not register any misfires, noid lights say all injectors are working...we're confused! Next we are going to try a cam position sensor, seems our spark advance is not responding well to engine RPM. We are stuck at 18 degrees and rarely go above 24. Any suggestions!???

How does it run COLD, for the first 2-3 minutes after start-up? If it runs OK then, the MAF is either dirty, or bad.

runs the same cold, warm or hot. MAF looks clean and obstruction free.

I would suggest a power balance test and maybe a compression test to find which cylinders are dead. Blown head gaskets are a common problem on the 3.8L engine (not sure if you have the 3.0 or 3.8). It may have blown between 2 cylinders.

Thanks, we actually got it running. We cleaned everything and checked numerous sensors etc. and finally brought it to the local shop. All they did was reset the computer and it ran fine. Go figure! We reset the computer SEVERAL times all to no avail, they performed a "hard reset" after looking at it for 6 hours and it started to run fine. I guess in order to reset the computer, you disconnect the negative battery cable, touch the cable to the positive and reconnect. Never woulda got that one...

I'll have to keep that "hard reset" method in mind. That's an easy possibility to eliminate early on in my diagnoses - at least the difficult ones!