Here's what I got: 02' 4.2 v6, flowmaster 40 muffler and recently did the "gotts mod" to it. After doing the mod I could only tell a little bit of a difference in terms of response. I would like to get a little more HP if possible and maybe a little more MPG. HP is the main thing though since its a truck and obviously if I were looking for MPG I would've bought a car. What kind of performance tuner do you recommend? Is it worth getting a tuner on a 4.2? I want something that is easy to use but also gives me plenty of options to customize.

Truck has 80k miles on it and stock everything other than what I said earlier. Any help would be greatly appreciated! Thanks.

 

You can expect about 11-12 rwhp and 17-19 feet of torque from a Sct tune in the 4.2.