Why is my vehicle stalling after replacing the fuel pump?

Hello,

So, does the engine just stalls all of a sudden as you are driving?
Are you able to start it back up afterwards?

This could be due to a faulty crank position sensor.
Faulty crank sensor won't be able to send the proper signal to the ECM and that can trigger the engine shutdown. After the shut down the engine may or may not start back up.

Take a look at these helpful guides:

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

I have attached diagrams below for your reference.

Let me know of any questions.
Thank you.

So, it just cranks and cranks but does not start?
This could be due to a bad crank sensor.
Are you getting any codes?

Take a look at the guides that I have provided above. It could help you determine the cause.