wobbley1

if you turn the ign on and pump the accerlator pedal about 5 time untill the engine manangment light flashes then the pump will run for a lot longer. then you can check the pressure at the filter by unscrewing the water sensor a bit if none comes out at pressure, and he pumping is working, the pump is at fault

if its a auto its not to bad to do done plenty of them if its a manual its a little tricky just make sure your lr garage give you the new type gasket other wise it will leak

dont think there is a set time i have done one on one i was changing the engine on its not that hard you need to remove sump front cover the hardest bit is undoing the crank pully its very tight

one thing to check is where the filter screws onto the filter head remove the pipes off the filter head marking where they go then remove the connector that screws to the head and check if one is blocked i had this on a customers car it was a little bit of dry glue from the after market fuel filtere ( from memory i think its the one where the black pipe connects) also once you remove the connectors one will have a orange flap in it make sure thats all ok and not ripped and the other will have a white valve in it make sure thats ok if noise still there change those two connectors