Please can someone help. I hace a diesel voyager that revs by itself whilst driving but the car doesnt go any faster, just remains at the same speed then revs like mad then cits our. The turbo is in good condition and has no oil leaking.then car imobiliser is not at fault i have blocked off the egr valve to try and stop this. It will happen hot or cold. Any help would be greatly appreciated.thankyou in advance

 

##Cuts out