ok when my car was in bogota thats 2600 mts above sea level id idled very very smoothlly but then i moved to the beach and i had the car moved in a tow truck and when it got here and i started it up and it had a very rough idle, i imagine its due too bad timing because the vibration absorbers are in perfect condition, anyways how can i adjust the timing on my car

its an 1985 190e 2.3 16v euro