Going along with your suggestions, I went to look at the "green wire" at ecu to eventually force the engine into full rich and full lean modes. Turns out somebody before me has grounded the green wire into the black wire in pin 5. So, this is why i am running full rich. check the picture that i have attached.

Also, there is a light grey wire coming out of the green wire casing going into pin 20, which looks to be factory normal.

did this mechanic do this because of a faulty ECU and he was just trying to get the previous owner on the road?

I'm thinking about putting the green wire where it belongs(pin 4, right?), and seeing what happens. OF course, I'll wait till your reply before i do anything. With this curveball, I'm starting to get a little scared of what might be unleashed when i try to fix something that a mechanic did.

thanks a million,
d