IPRs usually only fail because the HPOP is failing and throwing crap into the reg, same goes for the
ICP sensor. HPOPs fail when the screen under the engine oil cooler fails, allowing dirt to enter the HPOP.
If a failure is detected as crap on the reg I always replace the HPOP,
IPR,
ICP and screen. Most times I also update the engine oil cooler while it's out. 90% of the time the injectors need replaced due to mileage or wear and the standpipes, rail plugs and FPR get updated. Engine oil always gets changed to 5W40 syn., Motorcraft filters installed & 2 bottles of Rev-X oil additive.
Change the oil filter every 5k miles and engine oil, fuel filters + 2 bottles of Rev-X every 10K miles.
If the root cause of failure is fixed every time they seem to stay together quite well.