System lean and oxygen sensor possible, bank one and bank two engine light came on without any car problems
Usually when you get lean on both banks it points towards a vacuum leak or weak fuel pump. It is unlikely that both front oxygen sensors went bad at the same time...not impossible...but unlikely. If the manifold gaskets are worn it could produce a small vacuum leak when cold and you don't notice it because the system is in open loop and compensating with fuel. As the manifold heats up and expands the leak disappears and you never notice the issue but the module still sees the unmetered air.
SOURCE: Check Engine Light Problem
Codes that tell you your engine is running lean can be caused by a number of things. First thing to do (and cheapest) is to get some fuel injector cleaner and run it for awhile. Dirty injectors can cause these codes. I recommend lucas brand myself but there are several different cleaners to choose from. The second thing is checking your vacuum lines. If there is a leak it can cause the engine to **** in too much air and cause the codes. Anything beyond that gets into alot of mechanical work and should be done by a certified technician
SOURCE: 97 Mercury cougar xr7 v6. po443, po430, po171, po174,
Sounds like you have low fuel supply or a leak in intake system causing lean codes, check fuek pressure and volume first. Cat converter effeciancy could be caused by the lean codes, purge system sounds like solenoid failure, check for high resistance accross purge vent solenoid.
SOURCE: My check engine light is on, I got 3 error
Look for intake leaks, espeically near #1 cylinder. sounds like major intake leak.
SOURCE: recently had my smog done check engine light w 3
P0171 indicates a lean condition. The most common cause of
this is a defective mass air flow sensor. Also check if any vacuum
leaks. System Too Lean (Bank 2) Basically this means that an oxygen sensor in bank 2 detected a
lean condition (too much oxygen in the
exhaust. Note: This DTC is very similar to P0171, and in fact your vehicle
may show both codes at the same time. ----------- P0430 means you're going to buy a cat. (And you'll have to fix the coolant leak.)Catalyst System Low Efficiency (Bank 2) .Also check O2 sensors . Thanks.
P0174 OBD-II
Trouble Code
Technical
Description
What does
that mean?
P0174 - Fuel Injection System Too Lean Bank 2
Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Excessive Fuel Consumption
Possible causes
- Intake air leaks
- Front Heated oxygen sensor may be faulty
- Injectors may be faulty
- Exhaust gas leaks
- Incorrect fuel pressure
- Lack of fuel
- Mass air flow sensor may be faulty
- Incorrect PCV hose connection
Possible solution
Dirty air filter of faulty air flow sensor are common causes of the problem.
Bottom line possible defective Mass airflow sensor and or O2 sensor in cylinder bank number two.
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