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Q: Horrible acceleration, horrible fuel mileage, and misfire codes.

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When you give it gas the truck is slow to accelerate and often idles unsteady. fuel mileage is horrible 7-8 to the gallon.

My car has 155555 miles.
My car has an automatic transmission.

Hello. First task is to extract any problem codes, whether the Check Engine is set or not. There are many things that can cause the symptoms you describe: injectors stuck open, or fuel pressure too high, coolant temperature sensor malfunctioning (telling engine management engine is colder than it is), the engine running too cold, etc. To have this issue taken care of, I recommend having a certified technician diagnose the cause of the codes so that these issues can be resolved.

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