The factory CP4 pump has been a problem since its inception. With today's low lubricity fuels, the CP4 has been prone to premature failure. Without the proper lubricity additive, the pump runs very hot and wear much faster than normal leading to a complete failure that typically ends with the pump contaminating the full fuel system with metal debris. When this happens, the only recourse is a complete fuel system replacement including fuel lines, filters, injectors, fuel rail and connector tubes. A huge cost that could have be prevented. If you decide to keep running the stock CP4, please invest in using a lubricity additive. Otherwise, a CP3 conversion kit is what we would advise. The CP3 pump is a tried and true design that, while not failure proof, have shown they are a work-horse since the late 90's. The CP3 pump is also much easier to upgrade to a performance version when fueling over stock is a must to keep up with aftermarket injectors and turbochargers.