HI, I have a 20 gallon Challenger Well Tank model #PC66R in my basement. I currently have very low water pressure in the bathroom on the 2nd floor. Pressure does not seem to be an issue in the bathroom in the basement or on the 1sr floor. Could this be caused by low pressure in the tank? Pressure on the tank is around 50 psi when thereis no water activity in the house. When faucets are turned on it goes down to 40 psi before kicking in and shoots back up to about 52 psi. My understanding of this system is very rudimentary... so any input you may have would be much appreciated.
Thanks

Could this be caused by low pressure in the tank?
No, Problem is some kind of restriction in line to second floor. Probably a flow restriction not pressure.

Hot, cold or both, all faucets and toilet or just some?

Yes, it is on both hot and cold. The bath and both sinks on the 2nd floor are have very weak water flow, toilet seems OK and shower which is separate to the bath seems OK as well.

First thing to check is faucet aerators.