Is the oil pump part of the water pump on these and if not, are they known for failing?
Seprate pumps. You can take the sump off and clean the pick up pipe. Assuming the oil pump is in good nick.
Personally, if your not sure of the history of whats been changed i.e. the oil pump, I would refrain from doing 125 in 4th

for the time being until you get the pressure checked or even have it replaced.
I got my timing belt and water pump done last week. Oil pump and pick up pipe is at the end of this month. Once I have done this, hopefully my worries of planting my foot will be long gone.