I just got a 2000 gmc short bed single cab with the 5.3, when I floor it all the way the rpm hits the red zone and I have 2 let go of the gas for it to shift out , guy I got it from thinks it was tuned, maybe a superchip.. Would a dyno tune do the job?? And bout what would that cost..have true duels and a cai on the way..help please....thanks

 

A dyno tune would be great for the performance however any dealer and some tire shops can recalibrate your speedometer.
Where are you located?

 

A lot of the members here have the tools and skills to tune if you ask nicely.