1999 GMC Sierra starting

My truck will not start on the first attempt no matter how long I hold the key. It does not matter if it is hot or cold. It takes 3 tries every time. Now the back story. On a cold engine it would not start so my mechanic said fuel pump. I replaced that and nothing. Next he did a pressure test and determined it was the pressure regulator. I fixed it with that. I then took my truck to a friend who worked at a dealership and he put a super awsome fix all system cleaner. Not so awsome. The problem came back only worse. It does not seem to be getting more worse and it has been a long time. Any body that looks at my truck says there is nothing wrong with it. Any thoughts.