Originally Posted by prumora1
I have a 2000 expedition that has a 5.4 in it, I was wanting to give it a little more umph. can I change injectors to 24# and change the mass air sensor to fool the computer like what is done on 87 to 93 mass air mustangs.
No, it won't improve the vehicle performance. The "simplest" way to significantly improve the performance of these in a such heavy vehicle would be forced induction or a DOHC 5.4L out of an early Navigator. Both are $$$ and both would require an aftermarket tune. If you're just looking for a seat of the pants improvement, I would go for some steeper gears. The Mod motors were never known for being torquey, and the SOHC also suffered from about zero top end as well.