Sounds like your brakes may be binding. the most likely culprits are the rear brake cylinders, which tend to seize up when they are not used for extended periods. The car is trying to overcome constant braking resistance, which would explain the poor acceleration and reducing performance as the load inceases uphill. This generally applies to models with drum brakes, models with disc brakes are less prone to this problem, but can still have issues with binding brakes.
Cost to fix yourself £30, at a garage who knows £100+.
Alternatively, you could also have a major issue with fuel delivery, a blocked fuel filter is the most likely cause. Cheap and easy to replace. It could also be the injectors, although the car would run very roughly if this were the case.
Another possibility is poor cylinder compression, this will normally manifest itself when the car is under load, less so when it is stationary. Expensive and time consuming to fix.
Could also be an issue with the cars Engine Management System, faulty Lambda sensors, MAFFs or Camshaft/Crankshaft sensors can all contribute to poor performance. These seem less likely though given your description of the fault.
The bottom line is this: Check those things that are easy to sort out by yourself first, then if necessary take your car to a reputable mechanic to have the rest checked out. Mondeos are notoriously difficult to troubleshoot, but very easy to fix once you know what the problem is.
Suddenend, October 2010
