Question about 1999 Ford Expedition

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Engine light is on, got codes pulled.. one is a "knock", and one is a "lean" the mechanic couldnt tell me what they meant though! Help? Please

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It means that your engine is running lean " not enough gas to air ratio" and is causing your engine to knock "misfire". Start with the simple and clean your MAF sensor.

You can buy a can of MAF sensor at most parts store like Auto Zone or Napa and just follow the instructions on the can. This would also be a great time to clean out your throttle body also.

Thank you for using fixya and good luck

Posted on Aug 24, 2010

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They can both mean the same problem, I would be looking for a intake leak and there is so many vaccum lines it could even be a problem with you charco canister

Posted on Aug 24, 2010

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What does code p1131 mean on a 2001 ford taurus

P1131 Ford
P1131 Ford - Lack of Upstream Heated Oxygen Sensor Switch Sensor Indicates Lean Bank 1

Repair Importance Level: 3/3

Repair Difficulty Level: 2/3

Forum Code

Possible causes

- Faulty Oxygen Sensor

- Vacuum leak affecting bank 1 only

- Fuel injector problem bank 1

- Check for cylinder misfire on bank 1

- Engine mechanical condition

Tech notes

Though the Oxygen (O2) sensor, the Engine Control Module (ECM) has detected a lean system, which means that there is either not enough fuel or and excessive amount of air in the system. Start by checking for vacuum leaks.

When is the code detected?

The Engine Control Module (ECM) detected bank 1 oxygen (O2) at its lean limit

Possible symptoms

- Engine Light ON (or Service Engine Soon Warning Light)

P1131 Ford Description

A Heated Exhaust Oxygen (HO2S) sensor indicating rich at the end of a test is trying to correct for an over-lean condition. The test fails when the fuel control system no longer detects switching for a calibrated amount of time.

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Aug 16, 2015 | Ford Cars & Trucks

1 Answer

Ihave a chevy 350 engine i changed the carburator and now there is a knocking sound coming from my engine so i droped the pan and found nothing in the oil or in the pan i visualy inspected the bottom end...

I suggest tat you pull all the plugs and use a digital inspection light to inspect each chamber to look for a foreign body (nut etc) that made it's way into the engine when you put the carby on. . Check that the timing is correct and the air / fuel ratio is correct as if it is too lean ( vacuum leak) then you may have detonation from spontaneous combustion

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Hello, I need some help. I have a 1996 Honda Civic ex (automatic) D16y8 VTEC engine. Today I had a mechanic replace distributor with a new one (not rebuilt) from an auto parts store. The mechanic did not...

Yes, the ignition timing could be off enough to cause the symptoms and the check engine light.
I would take it back to the shop and tell them to set base timing, clear the code, and refund you the cost of the knock sensor and labor.

Jul 07, 2013 | Cars & Trucks

1 Answer

Peugeot 206 runs sweet, but high emmisions?

Even though it runs good, check for intake manifold air leaks. Use an old spray bottle and spray water on the seams and Vacuum lines. The RPM will change when you find the air hole.
What is happening is the air is creating a lean reading that is within parameters, but not suitable for the testing RPM. Sensing a lean condition, the electronics richen the fuel mix making it too rich. Or a dirty injector may be flooding 1 cylinder.
There are also additives which are suppose to chemically treat the fuel to knock down the high readings.
Finally, the testing equipment could be wrong. You are apparently NOT getting a check engine light and unless the O2 sensors are not functioning, the exhaust should indicate something is wrong with the Catalytics. Even if you lose a signal from the O2 sensors you should get a Code for that defect.

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2 Answers

Check engine light went on on my 2005 chevy silverado @ 102,000 miles. Never had an issue before. But I noticed that it has been knocking lately for about 15,000 miles. Mechanic friend said not to worry,...

Hi, it could be a wiring issue. I would check for a broken connection or bare wire shorting to ground. Usually though, when the computer loses the knock sensor signal, it will ****** the timing to a safe range that will not allow the engine to knock. If you tell me which engine you have, I can give you more specific troubleshooting steps, such as the reference voltage for the circuit.

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I have a 2004 ford escape with the 3.0 engine. It recently started shaking and running real rough. couldnt go past 40 then finally it died. i can barley get it started and when it does it vibrates real...

You either have a huge engine vacuum leak or the fuel pressure is low, this gives the lean codes you have for bank 1 and 2 of the engine, have these two items checked out.

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I have a 2002 chevrolet blazer with a 4.3, 4dr, 4wd. Service engine soon light came on, took it to the auto part store to code it they said knock sensor, 02 sensor, low evap voltage or something close to...

No I don't think so, knock sensor only work under engine load, when sensor picks up a ping or knocking, it will adjust timing, o2 sensor could be bad, and will save you fuel mileage, but a miss will also give you an o2 sensor code, running rich, have him check for cylinder miss first.

Aug 13, 2010 | Chevrolet Blazer Cars & Trucks

1 Answer

I have a vectra c 1.8 16v ,when i start the car it starts to backfire for about 2-3 min,then when i pull away 1st gear is ok but when i put it 2nd the car slowes right down as if i have hit the breaks,the...

You need to take it back to the shop you have a fuel problem and the engine light is telling you lean fuel condtion and the fuel pump is not working or the fuel injector. Ask them if they tested fuel pump pressure I worked on one of that vintage and I found that the wireing hadsome problems in the engine compartment. But have the code pulled if I knew the codes I could help you, and the 1990 will be hard to find a mechanic that knows how to troubleshoot your car, and you want to find a older mechanic to work on it. 19 years is a long time for cars now days. If I am remembering correctly you pull the codes by jumping two wires and the engine flashs the codes,

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Check engine light codes and troubleshooting

Sounds like you have a vacuum leak for the lean code and the misfires. I don't see a 473 code in my manual, but have a 463. The 463 is for the fuel level sensor open or voltage high.

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