2003 Ford F150 XLT Sport Supercab dismal fuel economy
I usually play with 73-79 Fords, but got this one a couple months ago. I like the fact it's quiet, has power everything and is roomy compared to my 79, but the economy is HORRIBLE. I figured having a 4.6 auto it would get the rated 14/19, but it don't come close. Granted I usually run 70 with the cruise on, but it gets a average (with 90 percent highway driving) of 15.3, which would be OK if it had power, which is don't. Small engine, big truck. It's got fresh plugs and filter which made no real difference. Not missing or anything.
Anyway, it has a 'Lightning' exhaust (aftermarket that exits in front of the rear wheels), and I'm thinking of getting a cold air intake, shorty headers, and a power programmer but wonder if it's worth the expense.
I can't seem to find any real world numbers on mileage and power. I don't trust the manufacturers claims in most cases. They seem to be, ah, optimistic.
If not, I'll just buy what I really want, a 04-05 4x4 supercab with a 5.4 so I can really complain.
Well,you wont get any power out of shorty headers or the intake!
The intake might help a little with throttle response and the programmers are good for about 20+ HP
If you want a power increase from headers, you have to get the long-tube headers!
Can't find any long tubes for the 4.6, 5.4 yeah, 4.6 no. I have found several sets of shorties though, Summit has some for 199.00 and some others have them around that price point as well. Never used shorties on anything, and this is actually my first American fuel injected anything. Never had a truck without a carb before. Ever.
Wasn't sure about the intake either, seems like a waste of 200-300 bucks but again, never used one on anything since most of my stuff has either been newer European or older American, other then a couple newer Crown Vics...
I'd love to see dyno numbers on some of this stuff to see real gains (if any) that can be had. Actually more interested in a few extra MPGs but power would be nice since the little 4.6 seems to be lacking. It's a really smooth engine though.
Almost forgot, what's the deal with throttle body spacers? Wouldn't the factory design it to where they wouldn't be needed? I've used carb spacers with good results, but I don't think it's the same thing.
Welcome to the world of computer control.
Your in for a new perspective.
..Carb spacers don't translate to fuel injection setup. A half inch plus or minu doesn't make a difference on an already long intake tract.
..Swerl plates don't do anything because they are to far away from the head ports and there is no fuel in suspension, to act on like a short carbed intake.
..The 4.6L is only 262 cu/in in a heavy 5000 lbs plus truck.
..The trucks in general sit higher than the older ones so mileage suffers a little just from that point.
..The engine's peak torque does not occur until well over 3000 rpm.
..So you can see where you normally run is well below the good torque range so throttle response suffers.
..To look at this another way, say the truck weighs 5000 lbs. With 8 cylinders divided into 262 cu/in, that is 32.75 cu/in per cylinder.
..At 5000 lbs the displacement to weight ratio is 5000/262 or 19 to 1 is not very good.
..Short headers will make it worse as they favor high rpm at the expense of torque.
..The computer is the control system. Trying to break in with hardware changes on the outside of the system and expect any great performace changes to occurr usually results in dissapointment..
..Last, do keep in mind that low end torque is the key for a truck. Horsepower is at the higher RPM range where the motor usually does not run unless you want to drive in that range.
..With my 02, the engine does not start to pull good until 2000 rpm and pulls the best at about 3200 rpm in the max torque range.
..Normally in OD the motor will be turning at about 1600 rpm on cruise depending on road speed so the torque available is low. In third at about the same road speed the rpm is around 2000 rpm still far from torque peak.
..So these are some of the reasons your expectations are not being met with the trucks in the 97 to 03 year range.
I've been thinking about just selling it off come spring and getting a 04-07 4x4 supercab like I wanted to start with and get a small car for my daily driver. I think I'd be money ahead with the miles I put on one. I'm spending about 200 a week in gas right now with the miles I'm driving.
Need to sell what's left of a couple cars I just got back after 5 years and they're both a mess. Still worth something I guess...
Anyway, what I was getting at earlier is when you drive a lot of miles, even a few MPG makes a big difference.