TheSchoenherr

Any help on this subject will be appreciated.

So today I replaced my 4x4 solenoid (4x4 works great now) but as soon as I did that my truck decided to throw an engine code. So I used my edge evolution programmer to read the code and it is saying that bank 1 is running lean, so my friend brought his scanner over and is showing the same thing. His scanner is also saying its having really bad emissions and that the one O2 sensor is really off. So I'm trying to figure out what the issue is, I also tested it with the old solenoid and it made no difference. Do you guys think its the O2 sensor? Anything would be good...

I'm going to start working on it around 10AM EST so the quicker the response the better.

My truck is a 2004 FX4 w/ 5.4L 3V. Only engine mod is a trans tune from my edge evolution.

lewissa81

How many miles are on your O2's? Those things need to be replaced, ideally, after about 60k. They start to give false readings, or simply become lazy. Fixing your 4wd system can also inadvertently fix a vacuum leak. Vacuum leaks allow unmetered air into the combustion process. I don't know if that's your issue, but it's something to keep in mind.

TheSchoenherr

Well as an update, I replaced all my plugs with motorcraft. There was champion in it for some reason but I didnt break any, then I replace two O2 sensors and everything is working better than before!

lewissa81

Good to hear you got her fixed. From everything I've heard, Champion plugs are terrible.

TheSchoenherr

Alright, Update on day 2

My engine is running lean again -_-

lewissa81

What specific codes are you getting?

effects4

which two O2 sensors did you replace? pre or post cat??

primalurges

Swap your coils from bank 1 to 2. A bad coil can give you a lean reading (weak spark, not enough emission).

JimmyB1232

Which o2 sensors did you replace? And what setting do you have your edge on? And do you have a CAI?