1993 Cobra Mustang Tune Up

I have an all original black 93 Mustang Cobra. Original owner with 71k miles, grey leather. This Texas sun has finally gotten to the cheap black paint Ford used. It needs a new paint job, but right now, I'm looking for a shop to do a good tune up on it. The last shop I took it to couldn't tune it up. I step on the gas and it almost dies. Anyway, anyone in the Dallas area ( I live in Allen) know a good shop for a rookie.
Thanks
Mark