Gauge pressure on the fuel rail right ? 35-40 PSI should hold for several minutes. Does it smoke (black smoke) at start up? Only question I have is what about a warm start, a leaky injector would likely give more trouble on a warm start since rich mixture is not required. Remember on the older engines (lawnmower types & motorcycle) you could tickle the float valve until almost flooded, the engine started better with the float level way high.Of course they had no injectors . You could try this : Crank the engine for 3-5 secs with your foot flat on the floor, this will clear any excess gas fumes from puddling if there is one. Then start up as normal & see what happens?