Looking for some help, I replaced the fuel pump assy. After replacing the assy it started surging after about 5 or 6 miles. At start and up to that point it worked great. I then removed the throttle body to find 4 out of 6 injectors leaking. So I replaced the CPI with a new revised MFI assy. I still have a surge just not as bad. Do you think I possibly got a bad fuel pump assy?

Have you checked the fuel pressure regulator? It might be getting bad.

check the electrical connections and fuel lines to make sure you didnt kink anything putting the tank back up

Sounds Logical, Unfortunately I'll have to pull the tank back down but Oh well. I'm trying that this evening. Thanks for the input

I changed the Fuel injector assembly which comes with a new regulator

Moved to Chevrolet mechanical and maintenance.

Surging is typically caused by the transmission, but in this case it does sound fuel-related. Did changing the regulator help? Did you disturb any vacuum lines during the install?

I don't see it being a fuel pump issues, but it is surprising this occurred after replacing the fuel pump. What brand fuel pump did you use? With the new updated injectors (with new regulator), i might look at what might of come undone when you replaced the fuel pump. Vacuum lines, etc. This doesn't sound like a fuel pump problem.