Ages ago our fiesta started to over rev when coming to a stop and depressing the clutch/changing gear. It was a random problem - sometimes it was fine sometimes really bad. It also used to under-rev at times and try to cut out.
We had it put through the diagnostics but they couldnt get error codes out of it. We then had a gasket fixed near the exhaust manifold and it seemed to fix it for a while (it was definately a lot quieter too) and we thought that was it, as we were told it would be running too rich and was blowing as it was.
But no, it came back. A couple of weeks ago we had a new back box fitted and its quietened the noise even more, and we are getting better performance, but for the last couple of days the car has been horrifically under revving as you slow, and coming to a stop you have to fight to keep it ticking over. IF you rev for a while, it will stabilise, but as soon as you move off and then slow again it drops like a stone.
We cant win with it - and have no idea what we can do to placate it! Please does anyone have any suggestions or a definite probability?
Cheers Helen