I have a Ford Fiesta 2010 Diesel 1.4. Recently the car has been struggle to accelerate when the gas pedal is being pressed. The engine still roars and the indicator will shoot up, but the car just over revs. If I press the gas pedal really gradually and slowly then it's fine, but the moment I put any normal amount of pressure it will over rev so I have to lift off and re apply pressure to the gas to drive properly. Couple things if it helps (1) Once i'm over 70 it doesn't happen much. I can put my foot down and the car will speed up as normal and (2) The car has not been serviced for just over a year. So yes I know I need to get this done asap, but not sure if this would be related? I do not know much about cars so don't want to go to any old mechanic and get conned so wanted to get a bit of an idea what it might be? Thank you!!
Based on your description and assuming you have a manual tranmission car, it looks like your clutch is worn out and slipping. Driving like this with an over-revving engine and a slipping clutch will only make things worse and more expensive to fix because other parts will now wear out and fail too. Get your clutch replaced ASAP.