Check engine light 1998 Ford Explorer

1998 FORD EXPLORER
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DC9595
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1998 Ford Explorer Check engine light is on. The codes are PO171 & PO174 bank 1 and bank 2 too lean. I've changed the Mass Air Flow Sensor, spark plugs, spark plug wires, oxygen sensors. I don't know what else to do. We have switched engines and the light was on before with the old engine & is on with the new engine. We did use the top part of the old motor, I'm thinking maybe the fuel injectors?

I had a vacuum test done too. That come back with no leaks. I've also changed a hose that was collapsed and that didn't do any good either.

Yes it is a 4.0 SOHC I'm just lost on what to do.
Sep 12, 2007 at 10:38 AM
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MERLIN2021
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Too lean = too much air I am thinking vacuum leak....is this a 4.0 with plastic manifold?Sometimes the gasket in between the 2 manifold halves is gone? probably sucked into the engine over time...get back to us...
Sep 12, 2007 at 11:07 AM
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MERLIN2021
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The intake manifild sits on top of the engine, the Throttle body is attached to it...It is black in color if it's the plastic one, the plastic ones may have come a year or 2 later than yours....But you should still check for air leaks....
Sep 13, 2007 at 2:30 AM
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DC9595
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[quote:70a04299dd="merlin2021"]The intake manifild sits on top of the engine, the Throttle body is attached to it...It is black in color if it's the plastic one, the plastic ones may have come a year or 2 later than yours....But you should still check for air leaks....[/quote:70a04299dd]


We will be checking this out this weekend. 1 more question, how do you know what bank 1 & bank 2 is?
Sep 13, 2007 at 7:47 PM
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MERLIN2021
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Very simply the number 1 is on the exhaust bank the #1 cylinder is on..Bank2 is on the side cyl 2 is on!
Sep 13, 2007 at 8:17 PM
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