I know that I my self sometimes have it and so do a lot of others with 05 and up Mustangs. I tried to look for a topic on this but could not seem to find it ? So sorry to rehash if there is one .
So my friend Spence ( Comox ) often has this happened and sent me a note that woke up another issue that I had set aside but maybe should not have.

Good Morning Ed,
Well I had my car in to have the gas inlet checked. The dealership couldn't find anything wrong with the installation, however the mechanic's personal opinion is that the fill tube is smaller than it used to be so it can't handle the higher rates of gas flow. Ford says nothing is wrong and that the flow rates at the gas stations are set to high and that I must use a slower setting. I figure it is bull, they (Ford Company) used to small a pipe and don't want to admit to it because a recall to fix it would be expensive. My nephew has an
06 Mustang and has the same problem as we. I wonder if it was put on the Forum what the response would be. If everyone with the newer Mustang is having trouble we could send the response to Ford and maybe change their mind. What do you think?

 

Oh Sure & Now I find the TSB Sorry Mod's feel free to remove this ?
http://forums.bradbarnett.net/showthread.php?t=15105
exept it's for an 05 and we have 07's ?

 

Ed, FWIW, on occaision I still have the fueling issue on my '07 GT/CS...I agree that the basic issue is the diameter of the fill tube...it' s just too small. I can get the nozzel in just the right position that it won't keep shutting off most of the time.

 

I've got an 06GT... and experienced the fuel fill problem on 1st fillup. It's happened 3-4 times since. Here's what works for me: (1) ALWAYS set pump as slowest fill speed; (2) Find a station with low to moderate pump pressure. Following these two rules, (knock on wood), it has filled without shutting off early. I know it's not a fix... but leads to less frustration.

 

I've had it happen once at a Union 76 on my (late) 05 Mustang GT, but it happened at the same gas station with my 95 Miata too. No problems with ARCO.

 

the attendant at one station told me vapor build up in the nozzle from the smaller fill tubes on the stangs, but he said to shake it out to get the vapors out and start again and that worked for me no idea if it was for that reason or not (I have no idea how he knew)