Engine Mechanical problem
1987 Mercedes Benz 300e 6 cyl All Wheel Drive Automatic 100000 miles

my mercedes 300e was only hitting on 5 cyclinders and it jus recently stop running when i try to start it up it acts like it wants to start but it doesnt so we poured gas into the carburator and it started but died quik it ran really rough and i took it to a mechanc he told me i need a new engine and that it would be to much to replace the cyclinders it no compression in three cyclinders i think thats it help me out what should i do i wanna keep the car i dont wanna sell it