I really hope someone out there can help me here I have a 1993 deville and I have taken it in for a complete tune up and had it lubed and all but it still tends to cut out first thing in the morning when I rach a certain speed and my service engine soon light keeps coming on I am at a loss as to what else I can service on it I am new here to the USA, from australia and well we dont have cadillacs over there so I am not familiar with the maintence on mine can someone give me any suggestions as to what couild be causing this problem