If you are not getting codes related to the maf or lean codes you can do more damage than good trying to clean it. I would see if the codes come back. I still think you have grounds missing somewhere. You had circuit codes on several sensors. This is usually a broken ground or missing voltage issue. Standards and automatics from what i have seen have grounds on the transmission bolts. Grounding the body to the engine as you did may have partially solved the issue by supplying a non direct path to ground.
One thing you could do if you have a volt meter is check to see what the voltage is on the map sensor between the b+ and ground IN THE CONNECTOR.
Artificial Intelligence is no match for Natural Stupidity