Question about 2002 Ford Explorer Sport

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Code #P0171 & code #P0174

1999 ford Explorer XLS with original 65,000 miles
4.0 SOHC 4wd

The codes in the subject line stipulate that bank 1 & 2 are too lean. Replacing the following parts did not fix the problem.

Replaced MAf sensor & check engine light came back on
Replaced right bank & left back 02 sensors & check engine light came back on. The

Please help if you can.......James have same issue with 2002 ford explorer sport 4.0 liter motor, I do not want to put on a lot of stuff if it does not solve problem, also code readout gives possible problem as a failed HO2S21 or H02S21.

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  • webuck1 Jul 07, 2008

    96 Ford Ranger, code P0171. Replace PCV valve, check hose, may be blocked.


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Intake leak either plenum or lower ford had problems with this look it up

Posted on Oct 29, 2008

  • carcrazy1 Oct 31, 2008

    pcv valve could be messed up or the hoses running to it


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The intake manifold gaskets need replacement as well as the o-rings inside - if you call FORD they should be able to get you the correct parts.

Posted on Nov 05, 2008

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Look, man here is the deal:
code p0174 - refer to the front cylinder bank
code p0171 - refer to the rear cylinder bank

Posted on Jun 22, 2008

Intake gasket leak

Posted on Aug 26, 2008

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Which O2 sensors did you change. Your car has 4. One in front of each cat (catalytic converter) and one behind each cat. I have a 99 explorer with 205,000 miles and I have only changed the ones in front of the cats. The other two are still oniginal. Check to see which ones were changed.

Posted on Aug 08, 2008

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Related Questions:

1 Answer

I would like to know what these codes mean

P0171 System Too Lean (Bank 1)
P0174 System Too Lean (Bank 2)
P0301 Cylinder #1 Misfire Detected
P0302 Cylinder #2 Misfire Detected
P0304 Cylinder #4 Misfire Detected
P0306 Cylinder #6 Misfire Detected

Mar 12, 2014 | 1999 Ford Explorer

1 Answer

Code p0171 p0301 p2700

171 is lean bank one. 301 is cylinder 1 misfire. There isn't a 2700. p0700 is a transmission code. Check vacuum lines This could be all the codes. Bank 1 is the left side of the engine, While standing in front of it. Not necessarily standing in the front of the car.

Aug 22, 2013 | Ford Cars & Trucks

1 Answer

1999 Ford Explorer XLT 4.0 SOHC 4x4 code P1151 bank 1

Ok this is either a shorted wire or bad connector or just plain a bad 02 sensor or a stuck injector or bad PCV needs cleaned. You stated it runs great i would go with Bad 02 sensor first or check for possible exhaust leak and last check for bad converter.

Apr 07, 2012 | Cars & Trucks

2 Answers

I have a 98 Ford Contour and these codes. - P0708, P0171, P0442

p0708 is transmission range sensor curcuit high output, p0171 is system to lean ( bank 1 ), p0442 is EVAP emission control leak ( small ).

Mar 20, 2011 | Ford Contour Cars & Trucks

2 Answers

Code p0171 system too lean bank 1

I could be wrong but that sounds like maybe an oxygen sensor (bank 1). Not sure what code i had on my car but the only bank 1 and bank 2 I heard of is the oxygen sensor but you can always go to autozone and they can check the code and tell you what it is.

Mar 03, 2011 | Buick Century Cars & Trucks

1 Answer

I am getting a code p0171 and p0174 on my 1999 ford ranger 3.0 liter

P0171 is a LEAN code for cylinder bank 1

P0174 is a LEAN code for cylinder bank 2

That means your car is getting a lot of air and not enough fuel which will make the engine Misfire and rough idle. Well i can say check your mass air flow for any dirt in it and the EGR for any leaks. And also the fuel pump and the fuel lines or any restricted fuel filter. Good luck bro

Dec 28, 2010 | 1992 Ford Ranger

1 Answer

My 1996 ford explorer did not pass e mission the codes i got from them arepo171 and po174 can you tell what these are so i can fix them

p0171 and code p0174 are lean codes bank 1 and 2 sounds like a vacuum leak, probably like upper intake gaskets this is a common problem for these codes if it runs bad cold but better when hot this is your problem

Apr 07, 2010 | 1996 Ford Explorer

2 Answers

Ford explorer ,4 litre. have code of P0171

You could be right but before going to all that trouble of replacing the intake gasket take a close look at the MAF (Mass Air Flow) sensor. Also look for a vacuum leak downstream of the MAF sensor. The MAF sensor may be dirty especially if you are using an "oiled" air filter and it was over oiled. Remove the MAF sensor and clean it with electronic cleaner. Make sure it is dry before reinstalling. If it is damaged, replace it. Also replace the fuel filter as a partially clogged filter has been know to set this code on some vehicles. Check all vacuum hoses and replace as necessary.

Nov 14, 2009 | 2001 Ford Explorer Sport Trac

1 Answer

Code #P0171 & code #P0174

The most common problem on a Ford with these codes is deteriorated PCV hoses. Check the hoses from the PCV valve to the intake manifold. Pay special attention to the rubber elbows. They often crack on the inside curve and the crack is hard to see.

May 19, 2008 | 1999 Ford Explorer

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