Not to beat this dead horse too bad... 
I see this issue come up often, and now that I have owned and daily driven both I have a few thoughts on this for those considering a 4.6 or 5.4 2V Triton.
Power: 5.4 wins hands down.
I noticed the difference immediately when test driving the 4.6 Expy. Accelerating, cruising, climbing, etc. What the 5.4 would do easily, the 4.6 seemed sluggish or had to downshift.
Fuel economy: Negligible difference
Both get about 15 avg mpg. On paper the 4.6 has a 10-15% advantage but I never saw it. In fact just the opposite, since the 4.6 needs to rev higher to get power, I've noticed it gets a little less mileage than the 5.4 on long trips in the mountains. On level ground and short daily drives the 4.6 is better, but not by much, at best it saw a 1mpg advantage.
Maintenance: 4.6... maybe?
IME the 5.4 is a little tougher to work on because it fills the engine bay a bit more. To my understanding the 5.4 has issues with the timing chain that isn't a problem with the 4.6 so, and this is just from my reading, the 4.6 may have a longevity advantage. The dreaded "shooting spark plug" is an issue with both models but probably not as bad with the 4.6 because it makes less power. But that's speculation.
Drivability/Towing: 5.4 by a mile!
Accelerating into traffic, passing, uphill, pulling a trailer the 5.4 is the CLEAR winner. Especially if the truck is loaded down with passengers and gear. The 4.6 just isn't enough engine for a 3 ton truck being tasked with truck things. It never really feels "underpowered" in normal driving conditions but under load you can tell the difference. It's night and day IMO especially on long uphill mountain climbs where frequent downshifts are a bit annoying.
Final thoughts. 4.6 is "good enough" but get the 5.4 if it comes down to it.
When shopping for a 2nd gen and deciding if you should go for a 4.6 or 5.4, all things being equal, the 5.4 would be my choice. That said, I currently own and drive a 4.6 equipped Expy and am happy with it. It doesn't feel underpowered for daily driving and is good enough for my needs. However I do know what it's like to own a 5.4 and it just better all around for a truck this size. Kind of like the difference between sirloin and prime rib. Both are steak but one tastes sooo much better.
I see this issue come up often, and now that I have owned and daily driven both I have a few thoughts on this for those considering a 4.6 or 5.4 2V Triton.
Power: 5.4 wins hands down.
I noticed the difference immediately when test driving the 4.6 Expy. Accelerating, cruising, climbing, etc. What the 5.4 would do easily, the 4.6 seemed sluggish or had to downshift.
Fuel economy: Negligible difference
Both get about 15 avg mpg. On paper the 4.6 has a 10-15% advantage but I never saw it. In fact just the opposite, since the 4.6 needs to rev higher to get power, I've noticed it gets a little less mileage than the 5.4 on long trips in the mountains. On level ground and short daily drives the 4.6 is better, but not by much, at best it saw a 1mpg advantage.
Maintenance: 4.6... maybe?
IME the 5.4 is a little tougher to work on because it fills the engine bay a bit more. To my understanding the 5.4 has issues with the timing chain that isn't a problem with the 4.6 so, and this is just from my reading, the 4.6 may have a longevity advantage. The dreaded "shooting spark plug" is an issue with both models but probably not as bad with the 4.6 because it makes less power. But that's speculation.
Drivability/Towing: 5.4 by a mile!
Accelerating into traffic, passing, uphill, pulling a trailer the 5.4 is the CLEAR winner. Especially if the truck is loaded down with passengers and gear. The 4.6 just isn't enough engine for a 3 ton truck being tasked with truck things. It never really feels "underpowered" in normal driving conditions but under load you can tell the difference. It's night and day IMO especially on long uphill mountain climbs where frequent downshifts are a bit annoying.
Final thoughts. 4.6 is "good enough" but get the 5.4 if it comes down to it.
When shopping for a 2nd gen and deciding if you should go for a 4.6 or 5.4, all things being equal, the 5.4 would be my choice. That said, I currently own and drive a 4.6 equipped Expy and am happy with it. It doesn't feel underpowered for daily driving and is good enough for my needs. However I do know what it's like to own a 5.4 and it just better all around for a truck this size. Kind of like the difference between sirloin and prime rib. Both are steak but one tastes sooo much better.
