Fiesta MK4 1998 model problem.

We have had this car in our family for about ten years and she has never let us down. Untill now! At 4500 rpm there is a big flat spot. It will push through it but best to back off to 4000 rpm were everything is smooth again. When there is any sign of a hill it starts to stutter. Like a mild kangeroo sensation. Soon as it has climbed the hill everything instantly returns to normal. The car starts instantly everytime and has regular services. I have asked the mechanics locally and as yes none have an answer. It is driving us potty. Any help would be greatly appreciated.

Chris.

[quote name='christy277' timestamp='1299240614' post='116864']
Fiesta MK4 1998 model problem.

We have had this car in our family for about ten years and she has never let us down. Untill now! At 4500 rpm there is a big flat spot. It will push through it but best to back off to 4000 rpm were everything is smooth again. When there is any sign of a hill it starts to stutter. Like a mild kangeroo sensation. Soon as it has climbed the hill everything instantly returns to normal. The car starts instantly everytime and has regular services. I have asked the mechanics locally and as yes none have an answer. It is driving us potty. Any help would be greatly appreciated.

Chris.
[/quote]

it could be fuel limiting so replace the fuel filter,its cheap,easy and eliminates a possible cause !

it could be one of the spark plugs... or indeed the fuel filter, both cheap and easy to replace :-)