my gage seems correct, but as im running engine sitting or driving the vehicle runs out of gas at half tank ?

Thanks for getting back to me Jim, If I read ur answer correct the tank float is what tells the gauge what to read, but the gauge seems correct. the gauge shows half a tank and there is a half of a tank, but the cars seems like it runs out of gas and wont start back up until I fill the tank all the way up.

If it starts after removing the cap, either clean or replace the vent valve, or don't say I told you to do this, but some have used a very small drill bit and put a hole in the gas cap for ventilation. It may screw up the pressure necessary in the tank to work the pump so ask before drilling. I know there will be some responses to this. Then again, that is old school thinking.