Hi, a friend of mine has just had his 53 2.0 TDCI C-Max in for service, during this they did some recall work as expected. He was told that a valve had been reset and also a voltage parameter adjusted, the only documentation giving was refering to a voltage recal. Since this has been done MPG has increased by nearly 10 to around 52 MPG, however, performance is down, i have driven it and it doesn't seem to have the punch it had before. I know that it's always a trade off, i.e. better mpg will mean possably lower power but is this because of a fix, if so, how exactly? or is this due to a E