trouble going up hill

[vidfan]

Hello,

I have a 2008 Toyota with 64k miles on it and I bought it brand new. Been having issues losing speed when going up steep hills.

Last year I was driving from Central Maryland to Cumberland and most hills/mountains I would drive up would cause my speed to drop from 60 mph down to 30 mph and I would have the gas pedal fully pressed. A few days after the return trip the engine started to vibrate and turned out I needed to replace the spark plugs. When I try to go up local hills that aren't nearly as steep as the ones on my trip, my car still seems to struggle to gain speed still.

Anyone have this happen to them before or have an idea what could be the cause?