P0174 / P0171 error codes

[cmoschip]

My mother has a 1999 Explorer Sport with the 4.0 and for the last 10 months or so it has running terribly when cold - usually only until the end of the block (first 30 seconds or so) and then it smooths out and runs fine. With the recent colder weather the problem seems worse - such a rough idle it barely stays running.

It threw a CE light last month and found a P0174 and P0171 error code - lean conditions on banks 1 & 2. Reset the ECU by disconnecting the battery and my dad found a pretty loose air intake where he had removed it earlier changing the thermostat. He tightened it and no CE light for a month although it still ran terribly.

Threw a CE light again last week with the same codes. She's got an extended warranty (don't laugh) but the local Ford guys want to start looking at all kinds of ridiculous stuff and I think they'll still end up costing her money with trial and error fixing.

Anyone know if these errors are common and if so what their cause is?

 

[yob_yeknom]

Ask about the 00M12 program. They should replace the intake gaskets and o-rings for free. Known problems to cause rough idle when cold, and definitely sounds like your problem since both banks are running lean.

It only applies if she has the SOHC engine.

Dead Link Removed

 

[cmoschip]

Thanks! I will.