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Q: Nissan sylphy starting and dying down soon after

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At first my car was giving out black smoke and I checked the spark plugs , they had soot on them. I changed the fuel regulator and spark plugs and now it runs with clear exhaust. However, a new problem surfaced immediately after. The car starts OK but dies down soon after starting. If I keep my foot over the accelerator it continues to run but not smoothly. As soon as I remove my foot from the pedal it does down again. What could be the problem

My car has 240000 miles.
My car has an automatic transmission.

Hi There, Black smoke coming from the exhaust is usually an indication of a rich fuel condition. When this happens, this can be the result of many things such as faulty fuel injectors, a failing mass air flow sensor or a faulty fuel pressure regulator allowing too much fuel to be supplied to the combustion chamber to be burnt. When this happens the result is an excess amount of unburnt fuel being passed through the exhaust coming out in the form of black smoke. I would recommend having an expert from Your Mechanic come to your home to diagnose your fuel system.

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