Tip & How-To about Mazda MAZDA6

Rough engine idle and Lean DTC codes caused by split air intake

Check the 5" wide rubber air intake hose at the convolutes for splits that allow unmetered air into the engine. When this happens, the MAF sensor does not know this air is flowing into the engine, so it leans out the mixture generating DTC codes for Lean, Bank 1 & Bank 2.

Use duct tape for a temporary fix and buy a new air intak hose. This hose runs from air cleaner box to engine throttle body.

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p1131 and p1151 codes in 2001 mercury grand marquis, how do i fix it?


Try cleaning the MAF sensor first, then check for any unmetered air getting into throttle body (leaks in intake hose). Bank 1 is the driver's side of the engine (or front on FWD) and bank 2 is the passenger side.

Mar 02, 2015 | 2001 Mercury Grand Marquis

2 Answers

Help on finding out wind star coads PP0171-/-P074-/-P0401


first PO171 o2 bank 1 s1 lean PO174 o2 bank2 lean
PO401 cyl 1 misfire
when an engine misfires the oxygen sensor will read the oxygen from that cyl sensor doesnt read fuel so every misfire is a air pump to diagnose we have to fix misfire first check the coil wires and plugs for cyl 1 use spray bottle with water run engine hot at idle spray wires with water if enging runs rough shakes or stalls then replace the wires dont spray with to much water if the wires are real bad you may not be able to restart engine

try this first once fix misfire clear codes and drive it

plz comment vote reply if you need more help

Jan 17, 2011 | Ford Windstar Cars & Trucks

1 Answer

What do p0171 code mean


Fuel system - Bank 1 lean.

This is usually due to a dirty MAF sensor heated wires. Remove MAF Sensor and spray the tiny heated wires with carb cleaner or MAF sesnor cleaner. ALso, look for air leaks in the air intake system that is allowing unmtered air to bypass the MAF sensor.
Your oxygen sensor is eprting that not enough fuel is going through the injectors. Look for splits in the convolutes of the big air intake hose. Also, the PCV valve could be bad
My guses is there is an air leak.

Dec 18, 2010 | 2000 Ford Focus

2 Answers

My girlfriends 99 ford escort has been running for a few months with the P0171 code on. I replaced the air and fuel filters and sprayed down the MAF sensor but it still wont idle at all. Next on my list is to replace the MAF sensor but I was wondering if since she has been driving it for so long like this will it have to be timed? Also ive heard it could be a vacuum line leak? Im not familiar with anything like that so ANY help is appreciated


Yes, a vacuum leak is the likely cause. Check all hoses attached to the intake manifold for leaks. If good, spray carb cleaner or ether on the intake manifold gaskets while the car is running. If the engine revs, you have a leak where you sprayed and will need to replace the manifold gaskets. Timing is controlled by the PCM, so don't worry about that. If you have any questions, please let us know.

Oct 28, 2010 | 2001 Ford Escort ZX2

1 Answer

p0130 and p0171 trouble codes showing after cv joint replaced.


A code P0171 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 may cause the MAF to become dirty if the filter is over-oiled. There is also an issue with some vehicles where the MAF sensors leak the silicone potting material used to protect the circuitry.
  • There could be a vacuum leak downstream of the MAF sensor.
Possible Solutions Possible solutions include:
  • In the vast majority of cases, simply cleaning the MAF sensor does the trick. 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 all vacuum and PCV hoses, replace if necessary
  • Check for a dirty fuel filter and proper fuel pressure
Usually the cause of P0130 is a bad oxygen sensor
, however this isn't always the case. If your o2 sensors haven't been replaced and they are old, it's a good bet that the sensor is the problem. But, It could be caused by any of the following:

  • Water or corrosion in the connector
  • Loose terminals in the connector
  • Wiring burnt on exhaust components
  • Open or short in the wiring due to rubbing on engine components
  • Holes in exhaust allowing unmetered oxygen into exhaust system
  • Unmetered vacuum leak at the engine
  • Bad o2 sensor
  • Bad PCM
Possible Solutions Using a scan tool, determine if the Bank 1, sensor 1 is switching properly. It should switch rapidly between rich and lean, evenly.
1. If it does, the problem is likely intermittent and you should examine the wiring for any visible damage. Then perform a wiggle test by manipulating the connector and wiring while watching the o2 sensor voltage. If it drops out, fix the appropriate part of the wiring harness where problem resides.
2. If it doesn\'t switch properly, try to determine if the sensor is accurately reading the exhaust or not. Do this by removing the fuel pressure regulator vacuum supply briefly. The o2 sensor reading should go rich, reacting to the extra fuel added. Reinstall regulator supply. Then induce a lean condition by removing a vacuum supply line from the intake manifold. The o2 sensor reading should go lean, reacting to the enleaned exhaust. If the sensor operates properly, then the sensor may be okay and the problem may be holes in the exhaust or an unmetered vacuum leak in the engine (NOTE: Unmetered vacuum leaks at the engine are almost always accompanied by lean codes. Refer to the appropriate articles for diagnosing an unmetered vacuum leak). If the exhaust does have holes in it, it's possible that the o2 sensor may be misreading the exhaust because of the extra oxygen entering the pipe via those holes

Jan 24, 2010 | 2000 Subaru Outback

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