That’s great that your Titan is still running strong—minus this one hiccup! The 2008 Nissan Titan fuel pump relay location is on the right rear side of the engine compartment near the intelligent power distribution module (IPDM).
Unlike other vehicles that have the relay inside the fuse box, Nissan’s IPDM is a proprietary technology that puts all the relays together in a different place. However, this should make finding them and locating the fuel pump relay far easier. Use your 2008 Titan owner’s manual to find the specific mounting location for the relay and replace it as necessary.