engine stumbles on cold startup

[T4Rscott]

Hi all,

Need some advice here.

I recently had a P0304 code. I ended up replacing the injector on that cylinder with another good used one, just until I can get my other 6 injectors out to Witch Hunter. While the newer injector solved the p0304 code, the engine stumbles when it's started cold. It does this for only 1or 2 seconds then smooths out. Could this be a sign of a leaking injector? Any other ideas?

Thanks,

Scott