i recently installed a Mac performace cai on my 5.4 04 f-150.now i,m getting intermitting codes.i can clear them by taking off the neg. or pos. battery post .the first time it happened though the dealer wanted to charge me for dianogstics. i thought these things were okay to install with out voiding any portion of my warranty

 

They can and will charge you the diagnostic fee. They may waive the charge if they find that the problem is related to their parts only. I would take it to your local Autozone or parts store that offers the diagnosis for free. You can at least see the code and do some research on your own to figure out the cause rather than getting charged a diag. fee from the dealership.

Most dealers are just looking for an excuse to void your warranty, whether the problem is related or not.

Good luck

 

Doesn't the MAC intake require a tune after installation? IIRC it will run lean.

 

It shouldnt require one, though on some trucks, some intakes will throw a code. It is most likely running a little lean