Joined: May 2008
Location: New Haven County
I'm assuming you have a 100% stock motor. I would do as others suggested. Use the 91 octane every time. That should take care of it. It may take a couple tank fulls to get all the 87 out. As STL mentioned. Seafoam will help clean the injectors and internals of any build up. This combination should solve your problems.
I had a knock issue with a canned tune. Had it dyno tuned and it was gone. Good luck!
08 MuStAnG GT Coupe Vista Blue
MT/3:55 gears/EDELBROCK E-FORCE SUPERCHARGER WITH COMPETITION AIR KIT/FRPP GTA's/Axle-Exchange Aluminum Drive shaft/BMR Safety Loop/Amsoil 0w-20/14" Shorty antenna