I'm also getting codes 173 and 177, these were Memory Codes and likely were the cause of my check engine light last week. The light popped on while slowing down for a light, and went away when I accelerated away from the light. I know I've been running rich for a while, so 173 / 177 aren't a surprise.
I've cleaned the MAF, which is a Pro-M 80mm (blue plastic housing). The wiring to the MAF looks ok. I have a voltmeter to test the wiring, but I'm not sure what the voltage would be at idle. Any ideas on testing the MAF?
As for the rich condition, I need to check for vacuum leaks too; wouldn't surprise me if I had a couple of split hoses. My gas mileage is about 10-11mpg on the street (driving like a grandma), and around 20mpg on the freeway. I have 3.73 gears and an AODE. The O2 sensors are new, and I changed them about a month ago just in case they were fouled. I reset the computer as well, but the gas mileage didn't change.
The MAF reading will vary car to car, idle setting to idle setting, etc. Mine's just a hair over 1 volt as I recall.
If that MAF signal looks ok, I like your plan to find any vac leaks you can. Also check the ECT calibration to make sure it's not telling the EEC the car is cold.