Dumb question but I have read on this forum that running a CAI and a aftermarket exhaust will cause a 5.4 to run lean. I am not a mechanic and I am curious if using a higher octain gas will help or hurt. Is there a way with out looking at the plugs to see if you are indeed running lean? I also read that a custom tune is the only way to fix this and that so called canned tunes will not fix this but could make the condition worse.
I tow alot and just want a safe dependable ride. Thats why I bought a F 150. I hope some of you mechanical people can answer my questions.

 

The 04s and some early 05s have a reputation of coming from the factory, running a near lean condition. According to Troyer, you can run a three inch AF1 safely with a canned or stock tune, but not the AF1 3 1/2 or some of the other CAIs. The exhaust is not going to affect you. To be safe, a custom tune is needed. Besides, to really wake these engines up, you need a custom tune anyway.

 

Very well stated

 

What size is the Volant, 3 or 3-1//2?

 

I am really curious if anyone can answer the rest of my dumb dumb questions, I understand the the one answer I did receive, thanks you.