QX4 Fuel Pressure Regulator

[daroutt]

I am looking for info on the fuel pressure regulator for a 2001 QX4. Is this a part that has a high failure rate or they somewhat reliable and very seldom needs changing? I have this engine surge issue I am trying resolve and with some good help from my local NAPA guys it seems to to be a fuel issue. They suggest starting with the regulator before tearing into the injectors but they were lacking good info as to exactly what the regulator does or doesn't do when it fails.

[Pwnin O'Brien]

I would recommend starting with the fuel filter. Have you changed the filter? The FPR is not an item that fails prematurely. I have yet to hear of an FPR failure on any Pathfinder or QX4. One option is to pull the vacuum lines from the FPR and fuel damper and make sure they are not clogged, preventing proper operation of the two.

[daroutt]

I replaced the fuel filter (car has 104K and this was a first time change) and no change in the surging and hesitation issue. I'll try the vacuum lines first. Thanks for the help.

[ARKQX33V6]

Check OBDII for any latent codes first. TPS will also cause surges. The joints in TPS get dirty and cause throttle to compensate. Also clean throttle body especially throttle plate. And check for vacuum leaks use small propane tank, un-ignited propane around vacuum lines. Cold temperature sensor failing will cause RPM to increase.