I bought a 2003 LB7 with 293000+ miles on it. The truck hadn't been driven in about 8 months but started right up. No issues except it surges sometimes. The rpm jumps about 200 in different rhythms. Sometimes quicker than others. It hasn't affected the performance of the truck. Fuel mileage and power don't seem affected. I've read about a fuel pressure regulator. Can anybody give me ideas where that is located and if that would be the issue? Thanks