O2 sim using spark plug non foulers?

[Aloicious]

Should my truck (98 Z71 350 automatic) have 4 O2's? It has this style pipe on it and I only see mounts for 3? ( http://www.summitracing.com/parts/MPE-23453 ) The plug I found looks exactly like the O2 sensor plug I tried the non foulers on? It is attached to the frame rail and is unplugged. What looks like the sensor wiring is still there, they just cut the sensor out instead of unhooking the clip holding the wiring to the frame.

you should have 4, IIRC one of the mounts is after that flange, so it would be on the other section of pipe that is not included with that setup. you can crawl under the truck and take a look to make sure.

 

[bluex]

Thanks for in info, I will check it tomorrow and maybe grab a picture of the location of the wires. If I remember right I dont think this one would reach that far...

 

[bluex]

I think I figured this out somemore today. The flange that should be on that pipe between the cat and cat back is gone as well. So the O2 I do have is the one that was behind that flange. On my next day off I'm going to get a new bung put in for the other sensor and see if I can get that light to go out.....

I will also get a price on doing a single Y-pipe, and a dual outlet muffler with dual tailpipes. Any ideas on pipe size? I'm thinking 2.25 for the Y and to the muffler and 2.5" on the tailpipes?