my 2001 blazer 4.3 vortec keeps popping codes po172 & po175 lt & rt banks to rich.what could be the problem?

Answer 1

could be one or a conbination of:
-faulty EGR valve
-clogged catalytic converter
-faulty oxygen sensor

Answer 2

P0175 OBD-II Trouble Code
Technical Description

System Too Rich (Bank 2)
What does that mean?

Basically this means that an oxygen sensor in bank 2detected a rich condition (too little oxygen in the exhaust). On V6/V8/V10 engines, Bank 2 is the side of the engine that doesn't have cylinder #1.

Note: This DTC is very similar to P0172, 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 P0175 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 problem

Possible 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)


P0172 OBD-II 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 problem

Possible 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)

Answer 3

Take off the vacuum line to the fuel pressure regulator off and check for gasoline in it. The vacuum diaphragms in those leak and you wind up sucking gas into the manifold.

Answer 4

Leaking injector(s). Quite typical.