infamous p0171 p174

[ioamnesia]

Yep, I got them too. Actually had a engine misfire code on one trip to autozone. Anywho here's the skivvy:

1998 Explorer Sport (2door)
OHV


Replaced
Mass Airflow Sensor
Both upper O2 sensors
All Spark Plugs
Upper Intake Plenum Gaskets (o-rings)
Tested
Fuel Injectors (16-17 ohms) if I remember
Vacuum (20-21 at manifold)

Idles a little rough (little) after the CEL comes on, smooth as silk if I clear the computer.

Assistance plz?

--Micah

 

[dynamite196]

I actually have this same problem on my truck 97 2 door explorer with the OHV and it's next on my list of things to do but basically what i've researched points to an air leak somewhere. The prime suspect is the intake manifold gaskets but it could also be on the pcv valve/hoses. Best way to test is get some carb cleaner and CAREFULLY spray it around those areas while the engine is running. If the rpms increase at any point, then you have found your leak. Notice I said do this carefully, obviously when you're spraying flammable sprays around a hot engine you need to take precautions so you don't blow yourself up.

 

[ioamnesia]

Tried vacuum leak test

Also did the test with carb cleaner and ether, not a sign of a leak