I have a whining sound coming from the engine on my 2005 vento V Thunder I can't figure out also is accompanied by lack of power. It only gets up to about 40mph in third gear and that is at full throttle

SOURCE: 2004 lincoln aviator having a strange whining noise from the engine

I have an 03 and around 30,000 miles the same thing happened to me . I took it to the dealer and the replaces the idler pully wich is what was making the noise .hope this helps you

SOURCE: vw vento 1996 automatic transmission problem

most likely the valve body or the TCM

SOURCE: Power brakes feel stiff like manual

Your having a problem with the vacuum booster,check the hose connection at the booster,if the hose is fine the diaphram in the booster is leaking and about to fail.

SOURCE: high pitch whining sound from engine

Check the power steering fluid if its low it could cause this. Also could be alternator, water pump, ac compressor, or idler pulley. My bet would be on the idler pulley, its the one that keeps the belt tension constant. Remove the belt and check this pulley for slack also spin it by hand.
Good luck, dont forget to rate.

SOURCE: whining noise from engine compartment

Its the pully. I have a 2006 and had the same issue. It went on for months and I was told it was "normal". Well the bearings on the puly were blown and it broke the belt while I was driving. Cost 20 bucks to fix.