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Q: Battery or Alternator

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The other day I was driving home the car hesitated, would not accelerate and almost all the lights on the dash lit up. I tried to jump start it but it would idle for about three minutes engine would race on it's own and then shut off. I had to have it towed. The negative cable was loose and I replaced it the next day. Jumped the car it did the same thing. Ran for about 10 minutes, raced once and shut off. I did notice some liquid come out of the tailpipe when it shut off. What do you think this is. I had a new block put in last year. I was told it needs oxygen sensors. could this be the problem?

My car has 148000 miles.
My car has an automatic transmission.

A: This can be caused by a variety of things. ...

This can be caused by a variety of things.

The first couple of things you may need to look into are the possibility of a vacuum leak, or the fuel injection system.

In order for your car’s engine to run correctly, it requires a specific air and fuel mixture to be maintained at all times. If this is ever altered, your vehicle’s engine will react in different ways, much like you describe.

One of the ways this can happen is when too much air is inducted into the motor which happens when there is a vacuum leak. Conversely, this can also happen when too much fuel is inducted into the motor. Either of these two scenarios will cause an imbalance in the air/fuel mixture causing a reaction as you describe.

This can also happen when oxygen sensors are not operating properly. The oxygen sensors measure the air/fuel mixture and relay any corrections to your car’s computer which then makes the corrections. If this sensor is not working properly, it can cause the computer to receive inaccurate information which will then relay an inaccurate change to the fuel system.

This can be a very frustrating problem to detect and often times requires the experience of an expert mechanic. I would recommend having an expert from YourMechanic come to your home to diagnose your vehicle’s hesitation concern.

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