I just developed the exact same symptoms with my 97 4 door 4wd Blazer w/ 4.3.
No trouble codes, it just won't start cold unless i put starting fluid in throttle body. My fuel pressure is 55, which is at the low end of the acceptable range. Whover figures it out first PLEASE post the solution.
If anyone has a link or other info about the fuel injection TSB, please post that as well.
OK, I figured my problem out. I was having the symptoms everyone else was having- on a cold engine, no start without starting fluid in the TB. It would start back up if it was warm, but if you waited too long, you would need starting fluid again. It wasn't throwing trouble codes, my fuel pressure was 55-56 psi, the fuel filter was installed about 3 months and 8K miles ago, cap and rotor are new
I installed the fuel injection conversion, and once I put it all back together it started right up, but now I have a new problem.
The check engine light is flashing, indicating a severe misfire. The code is a P0303 only, so it is just cylinder 3. Also, I can hear popping and pinging in the exhaust, which i think is unburned fuel from cylinder #3.
When I had the upper plenum off, I sprayed all of the fuel injector passage and the inside of the manifold with carb cleaner and SeaFoam, so the plug could just be fouled. I am going to pull the plug out tonight and inspect it.
Anyone have any other ideas ? I verified that the wire is connected properly at both ends, and the wires are only 5 months old.