I have a 2000 Nissan Max. About two weeks ago my engine light came on indicating to have it service. I had someone to take a look and was advised that my coolant was just below level. However, he added more coolant and advised me that he had to reset something I guess under the hood so that the engine light would go off. He did what he had to do 'cause the light went off. After he did that now I'm having problems with the car cutting off after I start it up. It will run for about 20-30 seconds and than cut off. The only way I can prevent that is continuing pressing on the gas. Not to mention when I'm at a stop light within that same time frame 20-30 seconds it begins to jerk like it's about to cut off. Do be mindful, I don't have any problems restarting my car after it cuts off. Can you please enlighten me on what the problem or what you think the problem is or is connect to and what should I do? I know nine out of ten I would have to take the car to get service, however, I would like to be a little educated on what the problem is so that way they would not try to take me for more than what it's worth.

Thank you so much for you time and expertise.