So, I finally got the truck tuned. 5* 87 perf/tow. It's a beautiful thing!!! I now have a race car in the form of a truck! Question is: I set the tires to 34.5 closest available size to 34.6 which a 325x65r18 is equivalent to. I checked the speed on a phone app and when my truck says 47, my app says 45. Sooo....even though a 325x65 18 is supposed to be 34.6, when I measure it, it is smaller. So should I put the measurement in?? Or is it just smaller because of the weight of the truck? Any ideas?

 

I have been messing with mine even though I gave MPT my tire size. My speedo doesn't match my aftermarket nav speed. I assume 5* asks for tire size as well before sending the tune?

 

They did, but as I installed it was checked as stock, so I checked 34.5 and 3.55 gears also.

 

My lighted up gear on my dash no longer shows up either. Did this happen to you?

 

Simply push the "+" on your shifter and they will reappear. It does this each time you reflash your tunes.

 

Been running the tune for maybe 15 miles and I threw an engine code. P0300. I guess it's a misfire code? Does this happen a lot running a custom tune?

 

I'm on the mobile app so I can't see if you have a signature . What engine do you have? If you have an ecoboost it could be spark blow out if your plugs are old and the gap is wider than .030
But to answer your question either way no its not normal .
I've been running tunes for three years on my truck multiple different companies and have never gotten an CEL

 

Hmm, no I have a 2012 5.0. That's good to know. Not sure a spark plug could be bad yet. It only has 38000 miles.

 

so i just got 275-70-18 bfg ta ko2's at costco. i was dead on to a T after isntall with x4 in hand. i loaded my 5* 87 perf/tow and did 10 or so hwy runs with different axle ratio's and tire calc's . im currently off my 2 mph but my speedo is dead on for mileage and navi so for now my 2 mph slowness is doable.

ill mess with no axle tune and play with tire size to get a +/- speedo within 1 mph but at 2mph off im ok with that for now!