I recently had a problem...my '
stang wouldn't get over 50 without shaking and "sputtering" if that's the word. Took it to the Ford Racing Shop and they coached me on the fact that the mustang I got a few months ago had the original fuel filter on it...however the car was 87k miles on it...should have been replace almost 9 times by now. I use Mobile 1 sythetic oil and he told me it would be a good practice to change out the filter every 10k miles during the oil change...back to the point,
I also had him do the injector cleaning (unhooked the fuel pump and ran the car off of the cleaner through the injectors). I was getting a CAI installed too while I was there and moved the car from one bay to the next...I could tell an automatic change in the accelerator. Between the filter and fuel injection cleaning/line cleaning, it cost me 225 bucks but it was well worth it I think. I would suggest at least doing this once a year (about every 4 normal 3k oil changes) based on research, advise, and personal experience.
ps...between the CAI and cleaning I'm getting about an extra 25 miles a tank on gas too! More horses and more money in my pocket!