Thanks for all the advice, had the reflash done yesterday and what a difference. Even Tech. said noticeable difference to him as well. anyway...thanks guys.

 

If you have the 5.4L engine, you definitely need to get the PCM update -- people have said it is like night and day!!

 

We've both got it (5.4), and the build dates are only 2 months apart.

 

The Lariat has the 3.73, didn't the FX4 come with the 3.55? That could make a difference.


Oh yeah I almost forgot... you should have got a Lariat.

 

Do they both have 4WD? That would make a difference.

 

I wouldnt touch a Lariat

There could be allot of things that cause it, its not that a lariat is faster but if its not 4x4 or its taken better care of, has something done to it, it would make a difference.

 

Why guess? First write down the tires sizes.
Second, read the rear end tag.
Post both of these things so we can make a more educated guess.
OK, I'm just curious...

Ask if he has a tuner. Ask if he had it reflashed.
No harm done, and he will be flattered that you are interested in his truck.
Get the hood up and take a look, see if he has a K&N, an intake, etc. Also look underneath at his exhaust.
If he's messed with intake, exhaust and a tuner, you ain't playing in the same league.
Chris

 

I can't believe you guys haven't touched on this yet. . .

or maybe its because every truck is different. I have a friend with a single cab flareside 4x4 with the 5.4. Scientifically, his truck should be able to kill mine because of my tires and my weight difference but thats not the case.

 

I'm probably wrong here, but I thought the FX4 came with the 3:73 rear end....if not that's probably the difference if you have the dog 3:55 instead.

 

My fx4 has 3:55's not a dog very happy with it performance, pull a 6000# 5th wheel camper with it 9-14 mpg depending where I go

 

and also larger wheels and tires. CA hit the nail on the head, we need more info to make guesses.

 

2004 FX4
25000 miles,
K&N Filter
5.4 Screw
355 Rear
Factory wheels & Tires

2004 Lariat 4x4
40000 miles,
bone stock
373 rear
Factory Wheel & Tires

He said he wasn't aware of a reflash, but he wife did take the truckin for a 30K maintenece, while he was offshore. (probably did it then)

 

Looking at my window sticker my FX4 was optioned at no charge with a 3.73 rear end gear.

 

It's most likely what I mentioned before...the 3:55 rear end is gonna make your truck accelerate slower than one with a 3:73. Now get a tuner and a cat back exhaust and you should see a big improvement.

 

Besides the gears, it could also be the driving styles of the two owners. The computer adapts to the type of driving the owner does. After a few passes at the local dragstrip, my FX4 felt considerably quicker in normal driving.

Also, look under the hood of both trucks to see if there is a sticker on either truck showing the PCM update was done.