So I have had my truck for about 1k miles. Took it on a nice 500 mile road trip right after gaining ownership (2007 F150 FX2 with the 5.4 and 112K). Truck performed flawlessly through the hills of southern Missouri near Arkansas. Anyway, I get a CEL today, 25 miles after filling up the gas tank. First thought was loose gas cap, took it off and put it back on, and still a CEL. Ran the odometer check (yes, I know, not very reliable) and no DTC's. Unhooked the battery for 20 minutes, cleaned the battery cables (although it wasn't really needed) and left the gas cap off the whole time battery was unhooked. When I hooked the battery back up and started the truck, no CEL and the truck idled smoother and quieter than ever!! Took it for a short drive and no "engine" light returned. My observation is this: I think the previous owner had a CAI on the truck and put the stock intake back on when he traded it in because - there is a bracket missing where the round rubber connection is on the intake and about 500 miles ago, I noticed this, so I fabbed a bracket and got the part that connects to the area right under the air filter to seat correctly (by using a heat gun and "expanding the opening"). Did my resetting the PCM cause the truck to FINALLY recognize the stock intake and make it idle and run better? Not sure, but whatever I did, it seemed to make the truck behave much better, especially at idle. Hmmm, any opinions?

 

Doing what you did reset the MAF sensor in the intake to now detect the proper amount of air.

 

Hi.

Doing what you did actually cleared the Keep Alive Memory (KAM) in the PCM where all the Adaptive strategy optimizations are stored (fuel trims, idle settings, etc)

Adaptive will eventually adjust all on it's own (it's always running). You just helped it along.

A KAM reset always makes the truck 'frisky' in the short term - it settles down some after a few drive cycles.

BTW - don't be surprised if the CEL pops back on. You may still have an underlying issue.

Lastly - if you suspect a CAI/WAI was used, better go ahead and clean the MAF and throttle body - probably not as clean as they should be. And hopefully the previous owner also ran a corrected tune fer the intake and not run the truck lean for an extended period.

Used truck maintenance history? I dropped a list of maintenance items for these trucks here for reference. You may wish to review them:
https://www.f150forum.com/f4/new-me-...9/#post3291654

good luck
MGD