Q: When I'm sitting in park my truck makes a loud bang sound

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Twice I have turned my vehicle on and as I'm sitting idle in park my truck has made a loud bang sound, no check engine light, no leaks, I'm not sure what the problem might be?

My car has 103000 miles.
My car has an automatic transmission.

Depending on the sound and the location of the sound, this may be related to a misfire/backfiring problem. Engine backfire is caused by an imbalance in the air/fuel ratio being supplied to the motor and will occur in one of two places. A backfire in the intake manifold is caused by a ratio that is too lean or not enough fuel. A backfire out of the exhaust system is caused by a ratio that is too rich or too much fuel. As there are many possibilities here, this may require the skill of a qualified mechanic such as one from YourMechanic to come to your location and diagnose your backfiring problem.

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