David, thats a good possibility. Under GM warranty when replacing the injection pump, they require dropping the fuel tank, cleaning it and putting a magnet in the tank bottom. For future metal (ferrous metal). I'm not sure what happens if any non-ferrous material gets in the system.
If they replaced the pump without doing this, and it failed under the pump warranty, I'd go back on them. If you installed it, then I guess its your issue. I'm not sure if rebuilder's state anything in their warranty about removing the tank etc.
Tom McCauley (DP Member #513)
"Tankers-ToyII" Loaded 05 D/A K-3500 CC, SRW. Deep pan on Allison w/Transyn. Edge Juice w/attitude, 4" Kennedy exhaust, 98 Gal. Transfer-Flow cross bed fuel tank, Leer 100XQ bed cap. Reese 14,000lb class V hitch w/ dual cam HP sway control. Tow 34ft. 32FKD Holiday Rambler travel trailer. GCW 20,360lbs