2003 Buick Regal Momentary loss of power with p0101/p0107

I have an '03 Regal with around 350,000 miles on it. Ran fine for a long time,
then it developed an interesting problem. Soon after starting up and getting
up to speed, it has a momentary loss of power. The RPMs will drop 500-
1000 for a second, and then it's back to normal. This can happen at 35 or 55.
Generally on my 25 minutes commute, it'll happen within the first 5 minutes,
then maybe once more.

After it does this, when I come to a stop, the engine begins surging while
trying to slow down or idle. The lights are surging with the engine. I have to
really hold the brake to keep it from trying to move forward. If I put it in park
and give it some gas, this clears up. It will idle fine until the loss of power. But
this idle surging always clears out with the application of more throttle (which
is sometimes hard to do while sitting at a red light).

OBD2 is throwing a p0101, p0107 and occasionally p0137. I cleaned, then
replaced the MAF sensor Also cleaned, then replaced, the IAC Valve. (Every
once in a while it will make a loud sucking sound from the throttle body, but
that's infrequent). The rough idle was killing it, until I realized that I had left
he MAF in when I sprayed Seafoam down the throttle body. I cleaned the
MAF and it no longer dies at rough idle. But I replaced the MAF anyway. No
change so far. And it's still throwing up the p0101 even after I replaced the
MAF.

I haven't yet replaced the MAP or the 02 sensor.

I'm stuck and need some diagnostic direction.