Dumb Question. I heard that running a CAI on an04 or newer 5.4 can cause the engine to run lean. Is there a way to tell if you are running lean other than looking at the plugs? I understand getting the plugs out is not easy on this engine. Will useing higher or lower octane gas help the condition? I am not a mechanic and really hope some one can answer this question. Just want my truck to run for a long time, I tow alot and don't want to kill it.
After reading around this forum I am afraid to put a "canned tune" from super chip or edge because many have said this can make the lean condition worse because I have a CAI.

 

Your alright if it's hooked up correctly. The 3 valve has reported lean conditions after install in some cases. The fix was just rebooting the PCM (computer) and the code would not re-appear in most cases. That might be what you heard. Quite a few Mustang guys had that problem.

Canned tunes is a big plus for your model. - If you go with the XCal tunes. There's a difference between setups. If you have a 3.5" tube , you' ll need a Custom/Dyno tune. 3.0 - Canned tunes will work.

 

AND you can't tell anything by looking at the plugs in a FI motor.
They normally look nearly white and lean.

 

Listen for knock under lite acceleration... If you hear a rattle from the motor under lite throttle... It's a sign of a mildly lean condition.. Also a sign of bad gas ,but that's easier to notice in general.