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Q: I have a 1991 Cadillac DeVille running very poorly very bad fuel economy she runs very poorly no power almost almost like it's bac

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Have a 91 Cadillac DeVille keeps falling on his face like it's not getting gas not sure what's wrong with it please help shaking backfiring was running poorly already replaced distributer and shaft plugs wires poor fuel ecc.replaced cadilactic converter and still sounds like i have an exaust leak runs so poorly can barely drive it

My car has 102000 miles.
My car has an automatic transmission.

Hello. From what you are explaining it sounds like you have a fuel system issue. It sounds like you are getting too much fuel. It can be caused by a leaking fuel injector, but most of the time it is caused by a fuel pressure regulator failure. It can also be caused by a failure in an oxygen sensor or in the temperature sensor. I start by checking the injectors to see if any of them are leaking. If not then the regulator needs to be replaced. If you need to have this checked, consider YourMechanic, as a certified mechanic can come to you to [diagnose why the vehicle is running so poorly] https://www.yourmechanic.com/services/engine-is-misfiring-inspection

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