I keep throwing P0171 and P0174 (both the same legend, reading lean and using more fuel than normal, is what it seems to be saying when I read it)
I have a 2003 Sport 4.0L 5 speed.
I have done the following:
Dealership installed all four O2 sensors (don't know brand but am sure that they would only use the OEM stuff and not Bosch).
Dealership installed six new plugs.
I removed the goofy, mismatched cold air intake. It was a mix of the main tube from the throttle body with an AIRAID short tube to a giant, oblong (not conical) K&N filter. This was my temporary solution because of the damage to the old filter that was on there when I bought it about a week ago.
It came with an actual AIRAID filter that was nasty, black with filth, and full of small holes. This filter also threw the same codes as the K&N that I slapped on there the other day.
Yesterday I scored a complete OEM air intake from a 2004 Rubicon. I installed it. I cleared the codes.
It started up with no CEL and ran really roughly for a few minutes. Then it smoothed out a lot and all seemed great.
Then the CEL came back on.
I checked the codes and they are the SAME ONES! ARGH! P0171 and P0174 - lean condition detected.
What else could it be? I do not see any cracks in the manifold. I know that one might be there because of the history of these things. But could it be something else - hopefully much less expensive than another crack-prone manifold?
Will driving lots of hard Interstate miles as my daily driver for commuting with these two codes be a problem or burn something up?
The motor also is running a bit hot, with the needle pegged at about the same place as the oil pressure one - just past straight up by about 1/8" or less. Can this be contributing or related? How do I lower my engine temp? The radiator is full to the top with orange stuff.
Pretty confused, and worried about driving this thing every day until this is sorted.