This may all be tied to a faulty MAF sensor. About 2 weeks ago, I picked up a salvaged unit from U-Pull-It. It seemed to be OK and matched my existing MAF. I was trying to determine why my '92 PAU was not producing enough power. The thread is over in "Other 3800 cars." I forgot what entitled it.
I swapped out my MAF and didn't see any improvement so I just left it in. The trouble was really tied to cracked coil packs on the ICM.
Since that time I started getting this code 57, and I got fixated on the BCS and BCA.
Well, today after reading the workshop manual some more I got to thinking that the ECM needs to determine engine load in order to control boost, and that got me back to the MAF. So, I dusted off my old unit and put it back in the throttle body.
A little test driving today has me thinking that maybe things are back to normal. The real test will be tomorrow on the "performance run" to work. So, maybe I got a bum MAF from the bone yard.
My original MAF is type AFH50M-02C; the bone yard MAF is type AFH50M-02E. I see from another thread that a SC MAF is going to be different from a non-SC, duh!