Well one day my dad was driving and the mustang GT/CS had a brake problem, and the TCS was messed up. So we took it in to the dealer, and this is the third time this has happened, so it was be pretty frustrating. We had to take the tune off so the dealer wouldnt clear it from the computer. My dad specifically told them it would run rough without it. And guess what? They say they had to do TROUBLESHOOTING. Yeah also the tune was erased. After we got it back though, we retuned it, and since the engine loosened up since the first time, they made it have 302rwhp vs. 293rwhp last time. Torque was 315 vs 313.

 

What are you measuring power with? Sounds like a fairly normal derivative considering ambient temps and such.

You're lucky they didn't change the strategy as explained in the sticky at the top of the mods section.

 

I was using a dynojet. My last dynotune was in March of 2007 before this recent one. I had the same mods during both, so 9rwhp is pretty good for a retune.

 

I actually read that wrong. I thought you were saying it lost power. The increase would definitely make sense after breaking in more.