30ish, depending on octane levels and type of plugs.
what year
By installing an cold air intake on a mustang
No.
Maybe 10 on its own. With other mods like a bigger throttle body and exhaust it will help out more.
From 5 to 10 horsepower.
I have a 1994 Chevy pick up short bed. and i have about 240 stock. i have put a cold air intake on it which is an extra 30 horsepower. I also put headers on which imporved it aswell. I have flowmaster exhaust and i have about 310 horsepower.
cold air intake
10 horsepower.
about 2 wheel horsepower
The cold air intake may add 5-10 hp to the 335 it was built with.
not much. between 2 and 5 if you are very lucky. ohh and sticking a huge opening at your tailpipe isn't gonna give you anything either.
Sound like a electronic problem. you should of posted the year and model mustang