I went out to my truck this morning to go to work, and a few blocks from home I noticed the orange/yellow engine light on on the dash. Truck runs great, no weird sounds, hell I just bought it a month ago and my mechanic checked it out before I bought it. Any ideas? Truck is 04 f150 supercrew, 106k miles.

 

Most likely evap related, usually won't affect performance of the truck, just sets the engine light because emissions standard aren't being met

 

have the code pulled and see what's up...they do it free at most auto parts stores.

 

It was throwing two codes p0171 and p0174. Both appear to be related to the mass air flow sensor.

 

Pull the MAF sensor and clean it with an electrical components cleaner, or better yet, MAF cleaner, available at the auto parts store. Very simple job, just don't touch the wires inside with anything other than the spray itself, and make sure it's dry before you re-install it. It's in the cool air intake tube, right after the air filter chamber. If you do a search here on the site, you'll find how to clean it. Don't break the wires, it's a $180 part.