Mondeo Tddi 115 2001 Fault Help Please

Hi,

Help please

I had what appeard to be a water leak back in october when some distance away from home so used radweld to seal the leak and my car seamed to be ok no more leaks and no more issues. About six weeks later the car started to struggle between 2000 and 2500 rpm in 4th and 5th gear, rev counter needle bounces back and forward and car chuggs until past 2500 rpm and then runs fine. I took it to a diesel specialist who claimed the water pump was leaking even though no loss of water I agreed to allow them to change due to the issue i had previously however once changed this never solved the problem. The garage thought it may be the EGR valve so they ageed to blank it off free of charge and still the same issue was there. They then suggested it may be a small electric pump under the rear wheel arch and i paid for the pump and they fitted it free of charge but still never resolved the issue so they worked on it for a while to reset the ecu as they thought that the ECU settings may have adjusted to compansate for the faulty pump. This seemed to sort the problem but car seemed to have lost a bit of power and my heater of all things just didn't to be as warm as previously to the settings on ecu being changed. The garage agreed to use a Vacume pump to bleed the heating system and that has solved the problem with the heater but my original fault is back an i'm now £500 down and back to where I started. Any help with this would be appriciated