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2000 Plymouth Neon Question: What is this pop/thump sound during acceleration?

 

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MechanicDIYintraining, Edgewood, MD, November 30, 2013, 19:53
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I noticed a pop/thump a few months ago out of the clear blue. It made the car hesitate to go for that split second it made the noise. I could feel it under my feet as well. It continued to do this once a day but only like every few days or once a week or so. Last week, out of no where it started to do the thump/pop like crazy and is still doing it. Check engine light came on. Took it to Auto Zone, they said a misfire in #2 and #3. Coolant reservoir keeps coming up empty, had oil down insode spark plug #1, oil level keeps showing empty on dipstick too quick. Replaced head gasket assuming it was blown in between #2 and #3. Still having the same thumping/pop during acceleration. Fine in park, starts great. Engine mounts r bad but this sounds more like a backfire/misfire but in the front of the car. Any help is appreciated. Very lost.

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  • Answer #1

    goodguy November 30, 2013, 21:03
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    If the popping sound is around the engine and you have a misfire you could have a bad camshaft or worn rocker arms.I would start by doing a compression test

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    MechanicDIYintraining, November 30, 2013, 21:39
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    Definetly going to check the compression. Honestly, it sounds like its coming from under the battery somewhere. Im the wife trying to help diagnose this thing. Compression test on the check list for tomorrow a.m. i can also describe the thump/pop as a sputtering thump/pop eith the beat of the misfire, if that makes any sense. It is definitely only when accelerating. During the thump it hesitates to go. I hope to god its nothing majorly expensive. Wishful thinking

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