Well, im stumped on this never ending p0141 chase.

Yea manual trans ecms are hard to come by and expensive, auto trans ecms are plentiful and typically in the $100-$300 range.

 

Hey Dm93 I was curious if you happened to know the easiest way to get to j/b 3. That appears to be inline of some of the 02 wires so I figured it may be worth a check.

 

I see where it shows it but I couldn't tell you how to get at it, I don't see a need though because unless there was a problem right at the splice L14 you would have problems with multiple other circuits plus that's the power wire for the O2 heater and you say you always have power there so that tells me it's good.
I was looking at the OE diagram for 03 (can't find an OE diagram for 02) and I do see a connector IK2 (pin 12) that the heater control wire goes through that might be worth checking out, I can't tell you for sure 02 has it since I can't find an OE diagram (Mitchell redrawn diagrams suck) but it may be worth investigating.