O2 Sensors

On a 95 how many O2 sensors are there? My Check engine light came on and put it on a computer said it was to running to rich and everyone is telling me its probably a O2 sensor I see the one in fron of the cat but I also heard there are four.. If there is I can I tell which one it is? Also has anyone heard of the fuel injection cleaner BG44K I heard its really awesome stuff wanna get other peoples comment on that stuff..

On a 95 how many O2 sensors are there? My Check engine light came on and put it on a computer said it was to running to rich and everyone is telling me its probably a O2 sensor I see the one in fron of the cat but I also heard there are four.. If there is I can I tell which one it is? Also has anyone heard of the fuel injection cleaner BG44K I heard its really awesome stuff wanna get other peoples comment on that stuff..

You will have either 2 or 3... 1 on the passenger side down pipe, 2 just before the cat, and 1 just after or just the 1 before the cat and 1 after

not sure on 95 I would gather rlith is right though

You need to do some more testing. It probably has another problem besides 02 sensor,
What code no did it have?
Run a fuel pressure check and watch for a fast leak down.
What engine and engine code?
In tank fuel injector is more to help keep the injectors clean rather that clean them.
To clean them you need a fuel injector cleaner setup.
MT

I posted this couple days ago just following up it gave me the code...
PO172 System too rich (bank 1). w-engine

I posted this couple days ago just following up it gave me the code...
PO172 System too rich (bank 1). w-engine

Well you got the code now give us the rest of the info.
The code indicates it is rich on bank 1.
Now look for somethig that would make it run rich on that side.
Any engine miss?
What is fuel pressure?
How is tune up end?
What year and mileage?
MT

The easy checks are the MAF (Mass Air Flow) Sensor may be dirty so spray it with MAF cleaner or electrical or brake cleaner. Also check for bad vacuum hoses intake to reservior can and others - would cause an idle drop also. Clear code and check again. Report back with results and if required more info on what you have done.

I posted this couple days ago just following up it gave me the code...
PO172 System too rich (bank 1). w-engine

Don't start more than one thread about the same problem. I fixed it for you this time.

P0172 OBD Trouble Code

Technical Description

System Too Rich (Bank 1)
What does that mean?

Basically this means that an oxygen sensor in bank 1 detected a rich condition (too little oxygen in the exhaust). On V6/V8/V10 engines, Bank 1 is the side of the engine that has cylinder #1.
Note: This DTC is very similar to P0175, and in fact your vehicle may show both codes at the same time.
Symptoms

You will more than likely not notice any drivability problems, although there may be symptoms such as a misfire.
Causes

A code P0172 may mean that one or more of the following has happened:
The MAF (Mass Air Flow) Sensor is dirty or faulty. Note: The use of "oiled" air filters (K&N, etc.) can cause the MAF to become dirty if the filter is over-oiled
There could be a vacuum leak.
There could be a fuel pressure or delivery problemPossible Solutions

Possible solutions include:
Inspect all vacuum and PCV hoses, replace if necessary
Cleanthe MAF sensor. Consult your service manual for it's location if you need help. I find it's best to take it off and spray it with electronics cleaner or brake cleaner. Make sure you are careful not to damage the MAF sensor, and make sure it's dry before reinstalling
Inspect fuel lines for cracks, leaks, or pinches
Check the fuel pressure at the fuel rail
Check the fuel injectors, they may be dirty. Use fuel injector cleaner or get them professionally cleaned/replaced.
Check for an exhaust leak before the first oxygen sensor (this is unlikely to cause the problem, but it is possible)