1997 OHV, Runs Great but has CEL P0174, P0171

[wicsmith1997]

History: New to me vehicle with No maintenance records.
Purchased April 2010. Thermostat, Plugs, Wires, and Fuel Filter replaced November 2010. Seafoamed engine via gas tank, and PCV valve just before changing Plugs.
Had CEL since purchased for EGR sensor. Previous owner drove it for ? time with CEL, I drove it 6+ months with CEL before getting new Egr Sensor 2.5 weeks ago and now have CEL for P0174, P0171(was CEL free for a week and a half).

Idles good, Runs good, accelerates good, mileage avg 16's a mix of city and highway.

I am thinking O2 sensors, maybe MAF needing cleaning, I'm praying its not the fuel pump.

I have used the search feature and most threads mention rough idle or hard starts which I am not experiencing. Not knowing when the O2's was changed last I'm leaning toward replacing those.

Thoughts? Suggestions?

 

[rego]

I have the same motor and situation. I plan on doing something with my upper intake gasket this spring. I'm thinking I may do some sort of smoke test if I can find an easy way to do it.

 

[ucluglee]

I would recommend using the search feature. MANY posts on those exact same codes.

 

[wicsmith1997]

I would recommend using the search feature. MANY posts on those exact same codes.

As stated in Orig post: "I have used the search feature and most threads mention rough idle or hard starts which I am not experiencing."

 

[swetrid]

It needs intake gaskets

 

[wicsmith1997]

I would think a vacuum leak or a need for intake gaskets would cause a rough running engine. Is it possible for that to be the cause and yet have no adverse effects to idle and running performance?

 

[Tricia]

Same codes, no problems

I've got the same codes on my truck. The guy at OReilly suggested the O2 sensor. I'll keep checking back to see what worked for you.

 

[joe doe]

its never the 02 sensor .dont throw your money away .if you got both those codes you need the upper plenum(big plastic air intake)lower "o rings".

i dont want to explain it all again so go to this thread here and read my explanation .read all the pages and the info you seek is there.
you will not have to mess with the lower intake unless you know for fact its leaking .but that is usually not the problem with these codes


its a common problem on these engines. dont throw money at sensors unless you get sensor exact codes .


http://www.explorerforum.com/forums/showthread.php?t=304739

 

[Tricia]

Thank you!

I really appreciate the advice. I don't know a thing about cars, except how to drive them . Thank you!

 

[wicsmith1997]

Hope it doesn't return soon as I post this; but at moment CEL is off.

I did not replace the 02 sensors. I did clean the MAF sensor.

Will keep monitoring.