Oxy sensor location

[Fuelaltered]

After replacing exhaust systems, decided to go all stainless.
Fabricated everything. Great. But fuel mileage is terrible, and exhaust pipe is black internally.
This is a 94, and only had one sensor. Where is the best place to locate it?
My 95 is behaving similarly. BTW, both are 4 cyl.

 

[Blmpkn]

Pre cat sensor id imagine?

I fabbed an entire new exhaust for my 96 last year.. sensor wants to be 6-8" past the collector with the stock header. If you don't have any stock pieces left over to reference I can take some more accurate measurements for you on Sunday.

 

[Blmpkn]

Also.. your truck still have a functioning EGR? No EGR will reduce economy.