Question about 2003 Ford Explorer Sport Trac
2003 Ford Exployer Sport Trac My check engine light keeps coming on, the reader shows codes 171 and 174.
I've done the following:
1. Replaced Gas Cap
2. Use high octane gas and added STP to clean jets
3. Replace the Mass Airflow Sensor
4. Replace all 3 Oxygen Sensors
I'm at a loss, what do I do now?
1. Trouble code P0171 means: Fuel System Too Lean (Cylinder Bank 1)
2. Trouble code P0174 means: Fuel System Too Lean (Cylinder Bank 2)
Not to replace the Valve cover that Ford just recommends it. The only difference is the hole where the PCV vavle goes is different. Replacing would have nothing to do with the code and the vehicle not running good. You only needed to replace the Bolts and of course the seals. The bolts are $6 each, $48 for just the bolts and another $17 for the Seals. Remove intake manifold.
The improved valve cover does not eliminate the oil in the intake problem, it does reduce it. Replacing especially since the TSB is very specific about needing to replace it (quote from TSB "VALVE COVERS FITTING THIS DESCRIPTION MUST BE REPLACED"). The cause of the P0171 and P0174 problems is caused by the oil getting into the intake and being absorbed by the rubber grommets on the bolts. That's why they have a redesigned bolt, by the way verify that the bolts they gave you had green grommets on them and not black. Unfortunately they kept the same item number even though they are different. So with the improved bolts and new seal you probably won't see the leak again, but by not reducing the oil going into the intake you may see the clogged EGR ports and deposits in the combustion chambers sooner than with the improved valve cover which could lead to pinging.
The reason you get the 171/174 codes is because air is getting into the cylinders from another source other than through the throttle body so the computer does not "know" about it. This is a vacuum leak and when the Isolator bolts stop functioning it allows air to enter from the Upper to Lower intake manifolds via the port seals.
The problem is most likely the intake-manifold gasket.
Posted on May 11, 2010
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Posted on Jan 02, 2017
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