In the past couple of weeks my wifes 98 V70 AWD Turbo has lost some of its VROOOM. The gas pedal seems to need more pressure applied to it. The accelaration from take off is slow and it will only go to about 3500 rpm and you have to take foot off gas to have chang up a gear. I tried the usual suspect and changed air filter and clenaed the Mass air flow. My next sep is to change fuel filter. Does anybody have any suggetions of what might have happened. Help!!!!!!!!