Check Engine Light Help?

P1131 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 1

This problem is sometimes caused by a vacuum leak somewhere on the engine.

Inspect all the vacuum hoses on the engine for any that are disconnected or leaking. If none are found, then start the engine and while it's idling take an aerosol can of throttle body cleaner and spray this around the intake area of the engine. If there are any vacuum leaks, the engine idle speed will change when the cleaner is drawn into the engine at the leak.

You also may have a failing catalytic converter. There are many signs that the catalytic converter may be in need of service, but two of the more common signs are engine performance and an odor associated with a failing converter.

A converter that is damaged can cause the engine to not function properly. For example, the engine struggles when going up inclines, it hesitates when you try to accelerate, or you experience a noticeable drop in fuel economy. If a tank of gas is not taking you as far as it used to, then it may be time to have the catalytic converter looked at.

An imbalance in the air-to-fuel ratio can cause excessive amounts of sulfur to be burned during the converter's operation. This can result in a distinctive "rotten egg" smell that is often associated with burning sulfur. Do not ignore that burning smell if you experience it while driving your vehicle--it could be your catalytic converter in need of repair.

Are there any other codes in the memory? code p 1131 does not mean the o2 sensors are bad it means the that o2 sensor-1 bank 1 in not switching as expected and indicates the system is lean! Due probably to a defective MAF (mass airflow sensor) this code will NOT be caused by a bad converter! you said that there was no vacuum leaks, but one thing you must check is the PCV line and hose which is a very common failure on this engine!!!

P1131 is a single bank code so that rules out the maf sensor. I would look closer at the easy stuff...Plugs, coil packs, injectors. Try swapping plugs and coils from left side to right side and see if the code changes to the other bank p1151 will be present then. Here are some other ideas...

Possible causes:

Fuel system

-- Excessive fuel pressure.

-- Leaking fuel injector(s).

-- Leaking fuel pressure regulator.

-- Low fuel pressure.

-- Contaminated fuel injector(s).

Ignition system

-- Spark plugs.

-- Spark plug wires.

-- Coil(s).

Induction system

-- Air leaks after the MAF sensor assembly.

-- Vacuum leaks.

-- Restricted air inlet.

-- PCV system.

-- Improperly seated engine oil dipstick.

Base engine

-- Oil overfill.

-- Cam timing.

-- Cylinder compression.

-- Exhaust leaks before or near the HO2S(s).

l Check intake air system for leaks, obstructions, damage and blockage.

l Verify integrity of the PCV system.

l Check for disconnected spark plug wires.

l Check for vacuum leaks.

no longer something to do with fluids. Flashing potential you're misfiring and that's something which would be extreme. A test of the code at this element will in simple terms inform you what cylinder is misfiring and that i wager there is extra suitable than one. Did you place decrease grade gasoline? That and the warmth ought to reason this. it could additionally be a foul gasoline clear out, undesirable spark plugs or undesirable injectors. occurs lots via fact the climate starts off to get warm out. i'd flow have the vehicle regarded at via fact there are a number of obtainable motives and it ought to get extreme priced changing factors that isn't restoration the concern. you will get fortunate even nonetheless that's ultimate to have it taken care of and end using if it keeps as misfiring can injury the engine actual.