Expert: Sean Halliday - 10/8/2008

Question
my mercedes benz c230 kompressor is having difficult problems. When i start the engine it revs up and down continuously and sometimes will not pull off and just shuts down. If i do get it started, It putters along until i hit 6th gear and then its fine. As soon as i slow down or break down the engine does the same thing again by reving up and down. if i do not press the gas while its in nuetral it will eventually shut off at a light or intersection. Could you please let me know what the problem could possibly be?

Answer
First question is did your check engine light come on?If not then its a fuel/air issue.It could be many things,the only way to diagnose this is have it looked at.I believe it is the fuel/air mix and possibly a reg problem or vacuum leak.It could also be the intake gasket but without the proper vacuum test,i would be guessing.Other causes are,egr valve,maf sensor or map sensor,sticking thermostat,temp sensor.There are a lot of sensors and components in this vehicle and a nightmare sometimes to pinpoint by just looking.The only way is to eliminate each one by testing.The best way to save time and money is to have it diagnosed by a reputable merc shop.They will find it in no time.