3sgte o2 sensor anomaly Options

[brianforster]

ok guys, so i found out recently a couple things:

DMC the original purchaser of this engine did not run an o2 sensor on the downpipe because he believed the lower temperature sensor to be the o2 sensor... car ran fine for him supposedly, well, fine enough to warrant selling

mark buys car from DMC, asks similar questions as me (where the heck is the o2 sensor wire) DMC says dont worry about it the lower one is fine.

car runs fine from him but apparently DMC sold it to him with rod knock, so has quarter mile customs rebuild it.

car runs fine when he gets it back.

no check engine lights at all throughout this time of 2 owners and the car hasnt seen an o2 sensor in months.

now im still in the process of tracking down the wire, its annoying, but i plan on doing it.

dan and art have said that it is impossible for the car to run right without the o2 sensor, and i believe them.

my point of making this thread is to ask people what possibly could have gone on during this engines life for 2 owners not to notice o2 sensor related problems.

(by the way mark reported like 22 mpg)

im confused, please help!

(note, this does not mean i wish to run without an o2 sensor, its just something id like to learn more about since this seems to be something nobody can figure out.)