RPM problem "Unstable" 2000 S80 Turbo

[wilsontorres]

Hi,last weekend i try tu run my car in high speed almost 100mph,and later when i stop the car,the engine start to up and down the rpm 500 to 1000 all the time,finally the engine stop and i get start again,and sometimes have burn odors ,i check by low of car and i saw a drop of wather dropping Simultaneously in the catalystic area with a/c off ,maybe i take a hole in the street i dont sure,please let me know any adivise ,thanks

[MadeInJapan]

ETM? Check the ETM section of this forum. Other than that, I have no clue.