On my 2002 V6 automatic transmission 3.8 Mustang ... There's a very small vacuum canister behind my glove BoxAnd it is missing a hose. Would that canister affect my fuelPressure or affect my fuel in anyway and keep my car from starting?

Hello, that is a vacuum reservoir for the climate control system. Your climate control probably does not properly move modes from the dash vents to the defroster to the floor. This vacuum reservoir supplies vacuum to then motor that changes those positions. Could it affect starting? Well, in as much as it affects engine vacuum, yes it could have an affect on drivability and engine performance. Whether it is causing your troubles or not remains to be seen via testing. www.repairpal.com/repair-shops