Nissan Repair: Fuel Regulator Relay, nissan 240sx, fuel pump relay

Question
1996 Nissan 240sx.  The car I have chuckles when warmed up under load, ie. doing a rolling stop in 2nd gear.  Before, I can just zipp through them without a problem.  I gave it a tune up; rotor, cap, plugs, and fuel filter.  I shook the filter and the gas came out a little grey from the "in flowside" but was clear on the "outgoing side".  Changing the filter helped a lot, but the problem still persist, driveable though.

I was trying to purchase a fuel pump online and it mentioned that I should check the the Fuel Regulator Relay before purchasing.  I have no idea where it's located and was wondering if you had any insight on it's location.
thanks for your help!  

Answer
The fuel pump relay should be under the hood in the relay box.  Sometimes it is in the fusebox under the dash.  You will need to Check under the hood first as it is marked.  On my Stanza it was under the dash and it was not marked.  Even the guy at Nissan could not tell me where it was located.  It ended up being the third one from the left.  Oh, there were four relays above the fusebox.  

However, in your case I would think it was the pump as the car starts and runs.  If it would not run and the relay to the pump  was not working the car would not start.  I will say, it is easier to change the relay than dropping the gas tank.  So, your call.