I fixed it now its broken

I changed out the starter yesterday. Now the car starts but only runs for a few seconds. Then it sputters and dies. Please help.

Why did you change the starter?

A common reason that a car would do this is an inoperative idle air control (IAC) valve. If holding the throttle down just a little will keep it running then its probably the best thing to troubleshoot.

But you could also have a failing fuel pump or failing ignition system components. What year is the car? Mileage? What is the maintenance history? Is the check engine light on?

Sounds like your fuel pump only gets power when the key is in the “start” position…Connect a pressure gauge to the fuel rail and observe your fuel pressure during the starting process…

Did you do anything else? Is the ballast resistor still connected properly?