revs slows down on its own

[mario_cy1]

Hello, i recently purchased a 08 focus zetec tdci (manual), the only problem i seem to have with it is when accelerating (in gear 3 or 4 normally) the car seems to slow the revs down on its own when the revometer is just climbing past 3000 revs. The only thing i can compare it to is when driving an automatic car and the feel of the gears changing on their own. I can't any posts that seem to mention the same problem. Any help would be much appreciated

[Sponsor]

[iminhell]

I was trying to find gear ratios to figure speeds, thinking you might be hitting a speed limiter. But I can't find ratio's.

Other thing I'm thinking is the turbo. It may be going bad. If it gets too hot the speed of the turbo and subsequent air volume (not boost pressure) may slow. This will heat the air more which will reduce power. The boost pressure may stay near the same though due to the heating.

We don't have the diesel on this side of the pond so these are just best guesses.

[doubles]

same guess here turbo getting to hot..

And welcome to the forum. im sure someone here that has had this problem or heard of it will chime in

[mario_cy1]

ok, thanks for the replies, the engine temperature doesn't rise at all when this is happening if that helps at all?

[mario_cy1]

Ok, i've realised that it starts doing this in the last 70 - 80 miles left of diesel and does it more the lower the fuel gets, thinking it may be something to do with the fuel pump or injectors, any help would be much appreciated!?