I put in a suncoast stage V with a 1056 converter and i have the same tunes i ran with my stock trans right now, the 3-4 shift is not smooth at all, it will slam and jerk into gear, sometimes it hangs for 2-3 secs then jerks and slams into gear and sometimes before it goes to shift it feels and sounds like im out of fuel(kinda like i keep letting off and on real fast), its not throwing any codes and i did the fast learn when it was installed over 4500 miles ago. Now my question, is it a tuning issue or is it mechanical inside the trans itself, all filters were changed today to be sure it wasnt a fuel filter. Its not a big tune im running yet(not over 500rwhp). I talked to the guy who built my trans at suncoast and he suggested changing the filter and checking the rail pressure then the desired pressure, its all good. It will be going back on warranty if i cant get it figured out, im hoping thats my last resort seeing as how im from canada and it takes 2-3 weeks to get the trans down and 2-3 back up any help or suggestions is appreciated.