That would be me! I bought my 2003 350 last November. It has 79k miles on it now, its a 4x2 with the 8ft bed and short cab. It has new continental tires that are stock size. In the winter I was only getting ~10mpg around town. That was unacceptable so I put in a new stp air filter, the old fram was completely black. Im thinking I might need to pull the MAF back out and give it a cleaning too. I drive like Im an 80 year old grandma from light to light now and Im getting around 11.5-12.5 mpg after the air filter and me learning to feather the pedal. The first owner never replaced anything so I Im guessing the spark plugs are the originals. Do you guys think new plugs would help gas milage, and has anyone ever tried different heat range plugs or brands to see if that helps? I've yet to try anything because 10 spark plugs isnt cheap. Since mine is 2wd I figured I would be able to get slightly better milage than some of the 4x4 super duty trucks but you guys are getting the same milage I am. :shrug:

Lastly, it needs a new muffler. The first owner removed the cat so its 3" pipe from the Y-pipe to the tailpipe. Which explained why it sounds like a diesel lol. I saw summit racing sells a 3" muffler to a dual 2.5" exhaust setup for the 4.6/5.4 trucks. They dont stock an exhaust for the V10 or super duty trucks but the 5.4 exhaust (summit brand) was only like $150. So I thought I could chop that up and weld it so it fits the V10. Anyone have advice on whether a single 3" is better or worse than a dual 2.5" from the cat back? Any advice on all this would be great. Thanks in advance.

~Dan

 

Congrats on your F350 V10 purchase. I hope you get many more trouble free miles out of it.

As far as the spark plugs, the consensus around here seems to be that these motors like the Motorcraft plugs best. At 79K on a '03, I would go ahead and replace the plugs/boots. I personally have not used anything than Motorcraft plugs in my Fords, but hang tight, I'm sure more guys will respond to your spark plug question soon.

As for the muffler, I had an '03 F250 V10 prior to my current truck and I put a Flowmaster exhaust on it from Summit. To be completely honest, the 70 series muffler gave the V10 a slightly deeper sound at best, but did not really improve gas mileage. Here's the exhaust I had on my '03 V10:
http://store.summitracing.com/partde...5&autoview=sku

 

Welcome to the site Dan. If everything is still original I would definately replace the fuel filter and the plugs. Use motorcraft plugs and whatever brand of fuel filter you want. Most exhaust systems do little to improve mileage by much.

 

Ive read several times about how you should replace the fuel filter but I never heard a legit answer as to why. Aside from the obvious reason that it gets dirty, do they clog up on these trucks abnormally??

And everyone around here uses motorcraft parts so thats definitely what I will use. It sounds like these V10s are reliable little beasts. Im happy about buying a gas hog now!

 

From what I've read a single 3" will flow better than dual 2.5" . Good luck with the truck. I miss both the SD's I had.

 

Welcome to FTE, Dan!

All good replies so far. Congrats on the truck!

A regular fuel filter change is just good preventive maintenance on these engines. There are many reasons for it, but mostly to get the best fuel delivery you can. And it also depends on where you buy your fuel. It's not the kind of fuel, but where it's stored...you could get some nasty stuff.

BTW - I have a '99 model and it has been almost maintenance-free. On the engine I've replaced one COP, the IAC valve, the EGR, the 90 degree ell at the the Throttle Body, the PCV assy, and the battery. All fairly low-cost if you do it yourself. I've changed my mind and think this is the best engine Ford has ever built. It was hard giving up on the old FE engines (352 and especially the 390), but the Triton takes the cake.

Good luck with and take care of it. Lots of great folks in here that'll help you do it, if ya ask.

 

Welcome to FTE, Dan!

All great info so far, I can't even begin to add to it.

Besides the engine-related maintenance, remember the differential (rear-end), u-joints, etc. They all need to be taken care of. Even though Ford says you only need to change the rear diff if the unit has been underwater, it can't hurt to change it.