Had the engine rebuilt finally after sitting dead in carport for 6 years. All seemed to go well with a few minor glitches. There is a sensor wire that seems to plug into nowhere. Near the radiator hose. Pictures attached. Mechanic coming again in morning to look for parts from a 1998 donor. Both 6g74 3.5. Help anyone? Perhaps a missed connection instead of missing part?

That is a connector for an ecu engine coolant temp sensor, which should be on the thermostat housing somewhere, not that familiar with your engine, but that sensor has to be on the water neck somewhere. The ecu uses it to determine if the engine needs cold start enrichment. It will probably start fine in warm weather, perhaps with a little cold stumbling, but I bet it won't start in a Tahoe winter. I bet your current mpg is pretty bad, and the exhaust smells gassy...

I don't think it is a coolant sensor connector. It looks like the one on mine that connects to a little module under the plastic deco cover. See the pic I attached...

I don't see the little module piece anywhere, but may be in the box of parts the mechanic left in the back of the truck.

Thank you so much for that picture. It really helps.

If you have more pictures, or can snap a couple more of the engine bay, I'd love it. The first mechanic I had started to take engine apart then passed away. So the second mechanic has been working off pictures and diagrams and from taking apart a different engine from a donor Montero. The whole thing has been a fiasco, but at least the car is driveable and just needs a few fine tune things.

BTW, if anyone needs parts off a full size 1998 Montero SR green, let me know. Fair shape overall. Lake Tahoe, CA.

I know what that parts does. It causes a willing suspension of disbelief...