Explorer Sportstrack is lean on 1 & 2 fuel banks


Old 04-21-06, 10:52 AM
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Explorer Sportstrack is lean on 1 & 2 fuel banks

Ford Sportstrack
6 Cyl, Auto trans
87000 miles

Trouble codes 171 and 174 came up on my explorer with the check engine light on. According to the guy from Autozone, it could be the (in order of priority):
1. MAF sensor
2. Oxygen sensor
3. Ignition misfire
4. Fuel injector problem

I wonder how could I test the MAF or the oxygen sensor. These parts are not very cheap and I dont want to guess and waste the other repair part. Also, once I replace the correct part, will it automatically reset the check engine light or is there a procedure to reset it?

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Old 04-21-06, 02:03 PM
Join Date: Dec 2001
Posts: 2,538
its probably running lean for some reason dont expect the o2 sensors, injectors, or ignition misfire to be causing the problem you might check the maf you can take it apart its probably built into the air cleaner but still comes apart and can be cleaned if needed.
could have a vacum leak or low fuel pressure causing the problem also.
how does it run how about when its cold and you first start it up how does it run then?
Old 04-21-06, 02:26 PM
Join Date: Nov 2001
Location: North Texas
Posts: 2,345
had same problem

Had same problem on a diffrent car a Toyota lean code and would hesitate with A/C on.
I did not want to replace parts either so I took it in to shop I kinda knew the problem same as you.
They replaced the MAF and all problems were fixed (hesitation) and the light has never came back on.
I have a code scanner and reset it two times prior to this and light always came back.
You have to clear the code with a scan tool and then you must drive around what they call a drive cycle.
You can not get a inspection till the drive cycle is done or it will come up as a not ready and you will fail.

Last edited by michael van; 04-21-06 at 02:37 PM.
Old 04-21-06, 02:56 PM
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I just cleaned the MAF sensor with a carbutor cleaner but it still the same. Whenever I step on the gas while it is on neutral the rpm does not get past 3000 rpm. It kinda go back and forth between 2700 and 3000rpm. I know the air filter has to be replaced too but I don't think it is bad enough to cause the check engine light. So I figured that the check engine light will not go away even if the problem is fixed unless the diagnostic tool resets it for me.
Old 04-21-06, 03:14 PM
Join Date: Dec 2001
Posts: 2,538
most modern vehicles have a rev limiter that would keep the rpm from going to high when in nuetral or park I suspect that is why it wouldnt go past 3000 rpm. if you experience the same problem while driving then there would be a problem.
I doubt that the maf sensor is bad they dont fail very often and explorer 4.0 liters was known for intake gasket leaks and lean codes to be set and if bad enough generally cause problems at cold startup such as a surge or dieing and would run fine once warmed up for a few minutes there would be no driveability problems other than the check engine light.
might check with your local dealer to see if there is any tsb on the intake gasket, or the 2 trouble codes set for your model.
Old 04-21-06, 04:19 PM
Join Date: Nov 2001
Location: North Texas
Posts: 2,345
it might go out

If you have fixed the problem with the MAF if that is indeed what it is it will take a little while of driving for the light to go out.(unless you have a scan tool that can reset it).They are a little pricey but since I have 3 OB2 cars I figured it would be a good tool to have.
However it might be that intake leak like bejay said.Let us know what it turs out to be.
By the way I also cleaned my MAF but it did no good.Anoter option is to have Ford do a diagnosic then you replace the part you will eat the cost of the diagnostic but that is cheaper then throwing parts at it.
Computer cars can be real frustrations as you are finding out
Old 04-21-06, 06:49 PM
Join Date: Apr 2006
Location: Floriduhhhhh Us of A
Posts: 611
171 & 174??............Lean on both banks ??...........Check your vacuum lines , paying specific attention to the PCV. Ford uses plastic lines with rubber elbows to connect. The rubber elbows decay, collapse and perforate over the course of time
Old 04-21-06, 07:15 PM
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My sister used the truck to go to work tonight so I will find out if there is any difference tomorrow. Also, thanks for the info about the RPM limiter which will prevent the car from revving over 3000 rpm while it is on Park or neutral. I keep you guys posted. Oh yes! I will definitely check the intake manifold for leaks.

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