I am currently seeing about a 2MPG improvement over the stock tune using the 87 Eco, around 10.9 up from 8.5. I still have not gone through an entire tank though. I also may not be getting into it as much as it is such a dog now.

 

Finally was able to leave town for some R&R this last weekend. Spent 3 days at a hot springs resort in a rented cabin with my boys. Hitched up to the snowmobile trailer and left town on for a few days playing in the powder. Had some pretty good hills along the way and noticed that under a load, the stock (I think) exhaust and new Y-pipe has a different resonance to it. Could hold our speed a little better pulling a hill in 3rd, but not anything mind-blowing. Not really sure it was worth the $100+ costs of the kit, nor the $180+ install price.

For those who run the tunes sent from 5Star, are you changing any parameters when programming or running EXACTLY what they sent? I've made changes for bigger tires and also lowered the idle RPMs a tad, but that's it. Too afraid to alter anything else for fear of a nuclear meltdown of our family car. I typically bump up the timing on my non-computer controlled vehicles to get a little more bottom end out of them, but haven't yet figured out how to do that on this programmer. Or can I assume that is already done in the tunes they emailed me?

 

I changed the tire size and gearing ration for mine to match my rig. Important for proper trans shift timing.

 

Just finished up one tank of gas with the 87 Eco tune. Started at 8.5 mpg w/o the tune, ended with 10.4 with the tune mostly city driving. I have yet to install the headers and Y pipe. Next is the 87 Perf tune to see how it differs.

 

 

With just the program change, I have immediately noticed that it is no longer upshifting so early. I am able to hold off the upshifts with an increase in throttle.

 

so, tuner, y pipe and basic tune up should help? Just got mine with the v10 and 147k miles. Got 10 miles per gallon on mine too. Has 285’s with no lift. Between not being able to switch the rear air off, which I’ll tackle another day, and running 93 in the HD F150, wife says no more cars for me. Will the above modifications help considerably? Not expecting a miracle but 10 in the highway with just me and no towing ain’t gonna cut it.

 

I'd start with fresh plugs and boots on an unknown used rig, that alone may get your mileage back up to more typical levels. Then once it's running better look into the tunes and Y pipe as the budget allows. Mine was running pretty good at 105K but a set of new plugs and boots did make a nice difference.

 

 

 

These motors use the Coil On Plug (COP) setup, there are no plug wires, the coil sits directly over the plug and has a rubber boot with an internal spring to conduct the electricity to the plug. Those rubber boots need to be changed along with the plugs as they do degrade over time and can bleed enough electricity to cause a miss.
For parts you will want:
Plugs - Motorcraft SP-479 (replaces the factory AGSF22WM)
Boot with springs- Denso part #671-0001 (Denso is the OEM manufacturer for Ford and much cheaper to buy than MC)
COPs - Denso part #673-6000 (If you want to have a spare or two on hand)

 

 

Spark plugs breaking while trying to remove them is an early 3V issue, so don't worry about that on the EX. I'm not sure what year your EX is but the early V-10s (pre '03) had only 4 threads for the plugs in the heads, so those motors sometimes suffer plug blowouts. Later models ('03 through '05) have more threads and the blowout issues there are extremely rare.
Factory torque value for the early plugs is only 11 ft/lbs, many owners here have gone with a slightly higher value around 24/26 ft/lbs, that seems to drastically reduce the plug ejections. The later improved design has a factory spec of 17 ft/lbs but I torqued mine ('05) to 32 ft/lbs with good results.

 

Finally used the EX to tow my trailer loaded with my car. Pure expressway for about 11.5 miles showed 8.4 mpg on the overhead console. On the local streets (30-35mph) it showed 7.4mpg. This is using the 87 Perf tune with 87 octane gas.

 

Question to all the gents who have the 5star, if I purchased the unit, would I be able to retune my X to a stock tune with it? I have been toying around with the idea of getting the tuner but being that I live in the big brother nanny state of CA I'd have to have it shipped to a friend's out of state as 5Star won't even sell it to me here. If I were to go the roundabout way of getting it, would it be worth it in the end? So far I am stock except for running the ScanGauge2 and do not have many more mods planned other than a possible mild lift and a larger Y pipe.