A check engine light will only be triggered if an extreme lean condition is detected. However, slightly lean (14.8- low 15 a/f) is still damaging but will show few signs. Also it varies truck to truck by what strategy came from the factory as Ford had over 100 strategies for the F150 alone. The only way to know if you're running lean is data logging and a wideband. The slightly richer tow tune is hiding some of the issue, but a custom tune is the only for sure safe way.

 

what kind of damage does it do and what should i be looking for. i dont want to hurt my truck... its gotta last another 5 years!

 

I don't know for sure that I'm running lean. I have never had a Cel come on or even flash. I have heavy hesitation and sputtering at high rpm's. Truck still gains speed but not like it's supposed too. And it happens sometimes. Not all the time. I only was wondering because of my intake.

 

Like everyone else has said get custom tunes for your edge, but if it was my truck I would take it off all together, I have heard too many bad things about the cai's to run one on my truck, not that I'm trying to start an argument or anything but I just wouldn't do it. If you wat to see what I'm talking about just do a search and read for yourself

 

To truly know if it's running lean you need to see the Air/Fuel map. And just cause it runs great doesn't mean its not lean. You can peak out HP and run strong all the while scorching the hell out of your heads.

 

I think you guys are making a cat into a tiger with this possible running lean issue. I spoke with a service tech at a local ford dealer, who's been to the ford engine classes on the 5.4 motor, and he said that the first year had this problem, then they updated the software for the computer and lean issue was no longer there. Now i will agree with you on this that some of these CAI could cause this, but not all of them. Hell half of these don't even flow more air then the factory air horn assembly. There mostly for looks and sound. Also if you run around all day running the heck out of your truck it does it no good either. Do what you want, but I think we have a lot of product pushers on this site that have no idea what they are talking about. They just think its true because uncle ted and billy from down the road told them. My two cents.

 

Also one other thought, why does it always seem like whenever you see these type of threads it always ends up with the person running a K&N CAI most of the time?

 

Have you checked fuel pessure? could have aweak pump or a line obstruction [filter] bubbabud 2011XLT SC ecoboost

 

Burning valves is the main by product of running lean. You can look at the spark plugs and tell maybe, however the best is with a wide band. Getting tuned is easy to avoid it if you have to keep the CAI.

The tech needs to take a few more classes. It's not so much the computer strategy that is the issue, it's relocating the slot style MAF that is the major problem. Yes the 04-05 had the most troubles with this, but the 06+ aren't immune to it just because of their stock tune. Read the link below for the MAF explanation. Aftermarket CAI don't flow any "more" air, it's still a NA motor so only so much air can go in. They attempt to reduce restriction, but usually come a cost to filtration. Here's a few pictures also from my travels of two 5.4L running lean and what can happen. The product pushers are those who haven't been around tuning and a dyno to verify their claims. Butt dyno's are a terrible measure.

https://www.f150forum.com/f7/edge-mods-93740/

 

Just looked at the stock air horn assembly that i took off, where the mass air flow sensor mounts its the same size as the S&B. So since this is the same, it wont run lean correct? I understand what you are saying? but the size of the tube is the same on both set ups. Thats why you cant say, that every CAI will cause this. I don't even really Consider the S&B a real Cold air intake anyways, because of the way its built.