Engine Mechanical problem
1999 Nissan Sentra 4 cyl Front Wheel Drive Automatic 120500 miles

the other morning i attempted to start my car, the engine turned over but would not start. this has never happened before. i decided to just go ahead and keep the key turned and see what happens. finally after about 10 seconds of the engine turning over it started. i pumped the gas pedal a couple times, i dont know if that helped or not, but anyway it eventually started. i kept it running for a while, shut it off, and it started right back up no problem. this happened yesterday morning, this morning it started right up as well. i took it to auto zone and had them run a diagnostic check on it and no codes came up. the guy i talked to there said it may be the feul pressure regulator. what do you guys think?

Could be the fuel pressure regulator or the fuel pump is failing