Without sounding like a schmuck, why have a muffler shop do a "tune-up"? Most of those places suck to have tune ups done. Not trying to knock them or their employees but for the most part, their techs are lower time, lower trade schooled, revolving door techs (again, for the most part) that might be doing a tune up on your model for the first time.... And ALWAYS get a quote on the work because you have certain recourse if the deviate beyond 10% of the estimate.
The best thing to do is to find a respectable, local mechanic that specializes in your type of vehicle, (for example, domestics) and has good techs. Another alternative, but more expensive with arguably better techs is at the dealer but it will be more costly. Most dealers do not charge flate from an accepted manual (ie Motors) and sometimes their "time" will be higher than the manual at an already higher (15-30%) labor rate. BUT, an expereinced dealer tech WILL know the ins and outs of a particular engine better than just about anyone else. SO when he does a "tune-up" he will know how to properly clean out the throtle body (extra charge?), any minute adjustments (really not many on EFI), etc...
Also keep in mind, if the truck is running rough or has performance issues, don't ask for a tune up!!!!! Describe the condition accuratley to the person writing the ticket / order and have them solve that first. If you spend 150 for a tune up and the truck still runs like crap on the highway when it really needed an Oxygen sensor instead, not the dealer's or mechanics fault. Also, japanese cars are more likely to run poorly when not tuned than domestics....
Ooops, babbeling
