hello guys

i need help before i go out and rip the turbo out of my Astra

i had it serviced it was fine was told to clean the EGR valve as it started to make funny whining noises and didn't like to accelerate and then a engine management light came on so i cleaned it put it back together and still was in limp mode i then took it out to see if i drove it it would clear its self i got to a set of lights and it just revved its self up to about 5-6k and wouldn't stop i took key out about 20 seconds later it stopped so thinking maybe the turbo had gone i got a tow home i just need to know what to do please help