I would start with the factory service manual fuel pressure test. One of those tests is pressure. Another test is to turn the car off and see if the fuel pressure holds for a specified period of time.

Harbor freight sells a fuel pressure test kit which includes adaptors for KE-Jetronic fuel pressure testing (and seems like EVERY other fuel system ever made - I think there may be an adapter for the Space Shuttle in there too!)

An "internal leak" in the fuel system could be the trouble with the cold start issue.