Hello! looking for help or guidance with my 98 f150...its a triton v8 4.6....For the first time since I've owned the truck, the check engine light came on. I'm in a bit of a spot where I have no help really, and I'm LOST as to where to begin dealing with this...I'm capable of minor repairs or changing oil...usually anything Im able to get info on....but I stopped at an auto place and the guy said," its ok, you got two "system too lean" reports or errors"??? He said it meant that the oxygen to fuel ratio was too rich in oxygen when it entered the combustion chamber........but that its fine, drive it....Seriously, that's nice, but is it true? I've found it easier to fix s*it b4 its broken too badly, I need my vehicle and a second (or more) opinion on the "it's fine"....plus she's been sucking gas more than normal = )

 

lean means more air than fuel.. ive never heard anyone word it like "rich in oxygen".. anyways a common problem for a lean code would be a cracked pcv elbow on the back of the intake..

 

thank you, it will take a bit, but i will go check that,

 

Sucking more gas than normal could just be the fact that you're probably using a winter fuel blend which is less efficient.

Your check engine light could also be from failing upstream O2 sensors. They're what report rich/lean conditions and they become more and more inaccurate as they age. They're supposed to be replaced every 100k so it's worth looking into.

 

If the codes were P0171 and P0174, the O2 sensors are fine, they are doing their job and REPORTING a lean condition. Most commonly a vacuum leak, with the PCV elbow being the prime suspect. Sometimes caused by a restricted fuel filter.

 

Thank you, I was not aware that there was a winter fuel blend, but can certainly believe it....I will keep the Upstream O2 sensors in mind, my mileage sits around 87,000 Im quite certain. Thank you, it's still currently a work in progress....

 

O2 sensors do NOT cause "lean" codes as they are simply reporting the condition.

"Lean" codes are, by definition, caused by too much air or not enough fuel. Period.