Nissan Repair: Fuel pump, better than yesterday, o2 sensor

Question
I just replaced the fuel pump and strainer in my car (also the O2 sensor and fuel filter, now it doesn’t run.  It starts and will stutter-run for < 30 seconds before it stalls.  The RPMs move up and down between 100 - <2000 RPMs, if I press the accelerator the RPMs drop down, jump up, drop down again then it shudders/shakes as it stalls.  There is also a thunking/thumping type of sound when it stalls even if I shut it off before it stalls.  When I shut it off it kind of stays running for a second or two.  I can repeatedly restart it and every time the RPMs rev to 1200 and it sounds right for a second the RPMs start fluctuating/bouncing up and down again then it stalls.  I put more gas in it today before trying to start it and it did do better than yesterday.  Yesterday it started several times no problem but it would stall immediately.

Answer
Hi Wendy -

I would definitely take it back to where it was fixed and have them check it out. Perhaps the connection to the IAC was not put back?

Hard to say without actually being there, but that would be my guess.

BTW, why was the car repaired in the first place, and were there any symptoms then?

The more info you can relay to me, the better -

Let me know -
aloha
calvin