We've used Seafoam on plenty of the cars. You just have to be very careful in not sucking up too much or you risk hydro-locking your engine.
Usually, pour it into a cup, turn the engine on, and use the vacuum line that goes to the brake booster to suck up the Seafoam.
****DO NOT POUR IT IN****
Let the vacuum slowly suck the Seafoam. Chances are, the engine will die several times in this process.
After that, let it run for about 10 minutes and then take it for a drive.
It is going to sound like bloody murder on your engine. Just a FYI.
As for the gas? Needles was on point. DO NOT PUT SH*TTY GAS IN YOUR CAR.... Racetrac, gas station gas, Sam's club gas.... all sh*tty gas.
I used to run nothing but Racetrac gas in my other car.... wound up putting my torque converter out.
Now I usually run only one station's gas (usually 7-11) but if I do have to fill up somewhere else, I will use Exxon on QuikTrip.