Well vapor locks are somewhat of the past. But still do happen, vapor lock is when fuel evaporation from excess heat in engine compartment during fuel delivery and causes sparatic hesitation or stalling, poor performance, and mostly noticed on trottle body injection or carbed engines. But with todays fuel delivery and psi's being used to maintain fuel pressure during operation, vapor lock is is a questionable diagnosis.
If you are smelling fumes from unused fuel or poor running, then that tells me that you have a air and fuel mixture issue which leads me to believe that you have fuel but not enough air mixture. So I would look at possibly a IAC valve, or Mass Air flow sensor, or maybe as simple as a coild pack getting too much heat and causing it to not operate correctly or within tolerance. Alot of times a IAC will start to fail after heat buids up in the engine bay and when you shut down and restart minutes or so later the engine turns over continually and not start. The the 2nd or 3rd time it starts up and you are fine. Hell it maybe a O2 sensor(s) mis-reading.
What I would do is go to AutoZone and purchase a cheap Decoder, a blinking light one, 20-25 dollars and read the codes out to yourself and see what you get, then work from there. If it is a lean or rich mixture, it should code out.
If it were I, I would start there and do some trouble shooting.
To answer your question about the fuel pump, stealership vs auto parts replacement parts. They are all the same and have the same possibility to fail at purchase or work as they are meant to. Some fuel pumps I have bought in the past worked great and others worked a few days and cut out, or did not work at all when I installed it. So anytime you buy a off the shelf part, it is 50/50 if it is good or not. That is why you keep receipts and warranty papers on all installed parts. But if you bought a pump because they said so, and you were getting fuel delivery before purchase, I would tend to believe it was a waste of money, and bad advice. Before I replace any part I look for a conjoining filter and replace that first before a pump or the like. The mark up an stealership parts are rediculous.
Hope this helps you out
