keep fouling glow plugs

[cheesecake]

well i just messed with the car and got it running good no problems then it just shuts off. i check the glow plug and it was bad i i put in a new one the car starts up and it runs for a bit then the plug went bad. im not sure what it is the car runs at idle at about 200 and when at wot going down the street reaches 300 wich i know is nbot good ive tried richening it up but i cant get the temps down.