Will and O2 sensor cause this?

[doobiess]

So for at the moment i check all plugs and they are kinda fouled...

I have bad mileage...

Out the tail pipe i have a constant fart sound.. and it farts like 5 times a second.. so almost every fire.. during idle...

It runs pretty smooth in idle.. put into Drive.. and then is a rough idle...

Also can smell gas...

I assume this is an O2 sensor... but for the 3100 Engine is it located on the back side of the engine?

[rixGAphx]

Yes, a faulty O2 sensor will cause the engine to run rich.
Though it gives lousy performance and milage, it prevents the permanent damage of burned exhaust valves that a lean mixture causes.

The O2 sensor is on the exhaust manifold in the middle of the rear of the engine.
Requires a special $12 tool for removal replacement.

Better check the cat, too.
Running rich for so long may have loaded it up, causing backpressure, farts, etc.

Good luck.
-Rick

[Hollakidd]

Whats a o2 sensor and whats its main purpose.

[doobiess]

Well its located in the exaust manifold.. and it checks for the oxygen lvls in the exaust telling the computer on what the enrchment lvls should be..

But over time they can go faulty or build up crap on them making them ineffective... in which causes loss of power.. a different smell out he exaust Gas mileage will increase.. and a rough idle.. reason for all that is the ECM will compensate by enriching the mixture.. even though it dosent need it.. and also it will clog a catalyic converter as well if left long enough...