Questions, What is the failure rate of the CP4 pump? What is the cause of the failure? and Is there any TSB on this?
I honestly couldn't tell you a failure rate. When my buddy talked to the mechanic at work he was on his 4th truck within 6 months. Granted they're government trucks that aren't treated well. But the kit was $400. To replace the fuel system is $8000 just in parts. So I went with the plan to get ahead of it.
There's something with the lifters in the pump. The tolerances are tight so the lifters eventually grind into the bores. I've seen a couple reports where the lifters actually turned sideways. Being that they have rollers that was very bad. Running some kind of additive in the fuel is supposed to help.
Fords knows, but there's no TSB on it.