I would be grateful for any advice or suggestions on the following problem: Recently, going down a long hill and going up a slight rise to a roundabout, when I went to change down the engine cut out. The engine started again no problem and off I went. However, since then, after this the same thing happens at the exact same spot. After starting it again using a little throttle, the engine felt very gutless and weak going round the next road followed by another long hill where it struggled for power even downhill; whenever the revs fell the engine 'throbbed' and struggled. At the bottom of another hill I floored the clutch again to stop at a junction, the car cut out again, and I couldn't get it going this time. Finally got it going again, opened the throttle and got it to about 4000 revs, anything less than this and the engine throbbed and cut out again.

After starting it again it then settled down and ran fine the rest of the way home, but it has since done in this on five other separate occasions, all at the bottom of longish hills. The car runs perfectly the rest of the time. So far I've fitted a new throttle body, new plugs and leads and a coil pack.