Afternoon,
Swapped out my exhaust manifold today - car had been sounding awful. Had a crack about a 3rd of the circumference of the 2-1 collector in it. Sounds much better now. Sh*t job though, getting to the bolts under the manifold was really, really annoying. Hopefully it might gain some performance too, for a 4.0, it feels really gutless...
Anyway, got a bit plug-happy when taking it apart. It's all back together, but I can't work out where this blue plug goes? Car starts OK, and isn't showing any codes. Does anyone know what it is, or could someone be kind enough to follow it on their car to see where it needs to go?

Many thanks.