I am currently having this problem and when I undo the big connector, the problem goes away. But my connector looks perfect, no sign of corrosion and I don't see any smashed wires. I guess I'll have to do the same and crawl in there and replace the connector and possibly some wires. After this...
I just replaced my cats and had a 125 come up. I cleared it on the way home, but will see if it comes back. Doesn't seem like too popular of a code, so hopefully it will be gone for good.
Anything to hold a tarp down? I bet if you used a regular truck bed net you could stretch it all the way down the sides. Looking really good, as soon as my tax return gets here I'm gonna get mine out for sandblasting and then into the garage until it's done!