when im am driving when its cold out but my car is mostly warmed up ill put it in 3rd and at 5k i will get a little stutter but it seems like when i beat on it and red line it wont do it. i dont know if its carbon , misfire , or i have no clue i just did plug coils and coolant flushes and oil changes . maybe not red lining enough

 

i just did all that should i re flash my computer ?

 

Now in sme other gears as well I think its because its really damn cold in the boston area