When i start my 95 chevy c1500 it stay started but shortly it dies unless i give it some gas and it also hesitate until it go faster than 40mph

Likely it's the Intake Air Control Valve, it allows the engine to receive air when you are not pressing on the gas pedal, they're an easy and cheap part to replace. I would recommend checking the IAC valve, air filter, mass air flow sensor (MAF). Some auto parts stores will check for trouble codes free of charge as a sterting point.

in 1995 these didnt have mass air flow sensors, they only started that with the vortec motors. Sounds like the motor is generally running rough if it wont idle and is hesitating. First thing I would do is check the cap and rotor, these are known for heavy corrosion in there even if they are fairly new. Throttle body fuel injection is very basic, only 2 sensors that would cause your issues, oxygen sensor since these basic fi systems are very dependent on them, or a bad map sensor. IAC will not cause a hesitation, tps will create hesitation but idle fine. You can also check the egr valve and make sure it is closing. Sometimes a piece of carbon can get stuck in them holding them wide open. I have also seen the injector gasket in the throttle body leak in turn pouring fuel into straight into the throttle plates.

I will go and buy the parts tomorrow to if it will fix it