jtsail, welcome to Sailnet. When you get a chance an introduction post in the Introductions section might be nice.
You've probably got air getting in somewhere. Bleed the fuel system right through to the injectors and see if that makes a difference.
From RFC 1925: "(3) With sufficient thrust, pigs fly just fine. However, this is not necessarily a good idea. It is hard to be sure where they are going to land, and it could be dangerous sitting under them as they fly overhead."