When I first started out I had the cruise set at 65 here in town, but when I hit the turnpike I cranked it up to 80. Just before I got on the TP my mileage peaked at 19.2

 

That's not bad. My 08 4.2 on 87 performance tune would do about 21 to 22 at 65 and at 75 to 80 maybe 19.5 or so. I am averaging my way to and from work. 52 mile round trip. To work has more uphill so I would get around 19 at 65 and 17.5 at 75 and coming back at 23 at 65 and 21.5 at 75. That was all according to my scangauge btw.

 

Well I picked up a used SCT SF3 3015 and a 5Star 87 perf/tow tune. Got the tune in about 6 hours, programmer is on its way. Can't wait to try it out!

 

supercrewfx4, any updates on how the tune is working for you? I've also got a 14 STX 5.0 and am just starting to look at tuners, I also do a lot of low rpm driving as my commute is mostly 35-40mph type roads and this engine/tranny combo seems to shift very early and seems to be lugging a lot as it gets into 6th gear around 38mph which is only a bit above 1,000rpms

 

TBillP603, I've had the tune for a few weeks now and I really like it. I think I am seeing an improvement in fuel mileage, but not sure how much yet. I drive about 50 miles a day about a 70/30 mix of highway/city, doing 80-85 on the highway, I average 15-16 on the dash, and going 65-70 on the highway portion I average 16-17, so far. Ive gone through about 3-4 tanks, but ive also had to haul quite a bit and its been hard to keep my foot out of the throttle. The overall the power is better, but not by a ton. Im seeing the biggest difference power wise in the low and mid range (which is where I drive), but there is an overall increase everywhere. Also, the raised rev limiter is fun on full throttle pulls. The 5.0 likes to rev. The biggest difference is the increase in throttle response, and the much much much improved shifting strategy. It seems like it chooses a better gear for most situations, shifts are firmed up but not overly firm or abrupt, and the throttle response feels like a real cable throttle rather than drive by wire. Tow haul mode is improved too. It seems to choose the right gear now to keep you in the powerband, and the downshift timing is way better. Overall, I think it just makes the truck much more easy to drive, and more enjoyable. I highly recommend the 87 perf/tow from 5Star.

 

Mine won't go into 6th until 45 mph. Do you have the gears displayed on the cluster?

 

When mine had the stock tune, it did the same. Now with the MPT 87 performance tune, it stays in fourth until 45 mph the shifts to 5th.

BiilP603 you might want to have your truck checked out, somethings not right. It should not shift into 6th gear that early.

 

Yeah, I've been to the dealer twice about the "shuddering, lugging at 40mph" They say it's normal, I say it's not! I think it's time for another dealer. Truck only has 3,100 miles on it. When you are accelerating hard from a stop it it will shift into 6th much later (higher speed) but when driving with a light foot to gently go from 35 to 40 it will kick to 6th.

Yes I do, I discovered you could turn that display on and off by playing with the manual shifting.

 

No matter how granny I drove the truck, I couldn't get to shift into 6th until 45 mph. What size tires do you have, and does the actual size match what is on your tire sticker on the door jamb? Could be the wrong size was loaded into the PCM at the factory or more likely the dealer swapped tires and wheels onto another truck and now your truck has the wrong size on it.

 

It has the 20" wheels and tires that are on the STX sport package, tire size matches the door sticker and original window sticker. That seems to be all the sealer will do is validate it has the right program. Like I said I need to try anther dealer, thanks everyone.

 

Compare your speedo to a gps driven speed app on your phone and see how close you are. If your within 2 mph or less than I would say the factory got your tire size and gear ratio correct in the factory tune. Then you only option is a custom tune to change your shift timing.

With the thousands of possible combinations with the different engines, tire sizes, and gear ratios available, it's entirely possible that the factory tune is bad and the wrong shift schedule is in it, and no dealer will be able to find out. If you continue to complain and escalate it further up the chain to the engineers in dearborn you might get it resolved.

 

Mine is Screw STX Sport 20" and 3.31 gears. It will not up shift to 6th until 45, and slowing from higher speeds it won't down shift out of 6th until it dips just under 45mph. That's the magical speed on my truck

 

I have an 2014 FX2 and do 25-30K miles a year, so I don't want to any tune that is too aggressive that could hurt the engine long term and would like to stay 87oct to keep the cost of fuel down. Looking at the web site it appears the 93 get about a 50hp bump, wonder what the 87 gets? any ideas?

 

1d say maybe 30-35 on 87..

 

Mpt ftw