bexster26

Hi I am really hoping someone can help me. I have a ford galaxy 1.9 diesel V reg. I bought it in April and since i have had it it never wants to rev higher than 2500/3000 revs and if i try it seems like it wants to cut out. Now lately I cannot drive it more than 30 minutes as althought the heater is showing half way on the gauge, it smells really hot, blows occasional grey smoke out and can start to kangaroo or just cut out. The only way i can continue to drive it is by turning it off for a while to cool then carrying on for another 30 miles or so! my husband has checked it over and cannot find the cause, please can someone give me some advice? many thanks