Hey guys, I’m new here and this is my first post. I have a 2003 expedition that I got a wicked good deal on. It is the Eddie Bauer with 5.4 and 4wd. And i love the living **** out of this truck, will definetely be getting a newer model when/if it dies. The previous owner lacked on some maintenance, so I’m working out a few “bugs” that I am almost stumped on so naturally forums are the way to go. I’ve searched some threads but haven’t found any super similar issues, so I’m sorry if some of them are similar but I haven’t found any close enough for satisfaction.
anyway
the first more prominent issue right now with it being spring, is this truck is literally incapable of revving past 3200 rpm’s, and stops making any power after like 2400 rpm’s. No check engine light, it doesn’t burn an excessive amount of oil, and trans fluid looks and smells good. There is a slight not so rhythmic clatter coming from near the catalytic converters on the drivers side, not the passenger at all. I’m also getting like 14mpg on the highway, while my dads f-150 with the same drivetrain gets 17-18mpg but has 200000 miles more. The dpfe hoses pop off if I get on it too hard, so my assumption is the cats are clogged and falling apart. My problem with that conclusion is 1.)no check engine light for o2 sensors and 2.)if I do gut or cut the cats, will my engine light stay on and mpg not get any better? I’m not expecting hybrid gas mileage but I think 16-17 much much better than 14 highway/9city.

the second currently less prominent issue is my 4wd will not come on when it gets warm outside. I flip to 4hi, I can hear the actuator click, sometimes the light comes on for a split second, sometimes it doesn’t come on for ~2 minutes, but most of the time it won’t come on at all. It was a cooler day today so I flipped it into 4wd and it came on immediately but I didn’t get a chance to see if the front wheels actually had power or not. When I switch into 4lo, it goes into 4lo effortlessly regardless of 4hi, and gets the extra torque, locked the front wheels together, but again I haven’t had a chance to see if the front wheels have power. I’m 99% sure they do in 4lo, but I’m not positive so I don’t want to say they do.




sorry if that was a lot to read, but I greatly appreciate your time and knowledge.

 

You might consider replacing the fuel filter for starters since you have no real idea of maintenance done.

Also ,you can't compare the weight of an Expedition to a 150, therefore the mileage is not comparable.

The 5.4 is not known for great mileage, so you might as well start at the beginning and start with airing the tires to the proper pressure, spark plug condition and so forth. If you are not sure , follow the schedule in your owner's manual. Oil change schedule is critical as well as the correct quality and spec motor oil.

If after you do those things might be a good move to have a check of the data stream info done to see what may not be working correctly and still not throw any .codes..
I believe you are correct with the conclusion of a converter problem which could have been caused by neglected maintenance..

 

what is different between a 2003 expedition with a 5.4 and a 2002 f150 fx4 with a 5.4? I know it’s the same motor and trans but I haven’t crawled under both and looked for differences.
I will replace the fuel filter soon and see if that helps the problem at all, I’m not so worried about gas mileage I’m more worried about it taking 1-2 minutes to get to highway speeds. I figured gas mileage was a byproduct of fixing that.

 

To answer the question of difference, check the sticker on the door pillar and compare the weights of each vehicle.

 

the gvwr is only a 400lb difference to an extended cab fx4 and a expedition 4wd, but 400 lbs doesn’t account for almost 25% less fuel mileage. Or the difference in being able to get on the expressway and almost having to avoid expressways is what I’m saying. I’m not saying “they’re identical trucks so they should drive identical” I’m saying they’re damn close to the same so they should drive damn close to the same.