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Q: vehicle is stalking and suddenly changing its RPM

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I washed my car engine with engine cleaner in car wash and later after drying, it started with new problem of stalking engine and smoke. Engine used to run smooth and clean before the car wash and after, it started making weird noise and not picking up the accurate speed while giving the accelerator. and at particular point of speed it suddenly reducing its speed and sudden changes in the RPM.. Don't exactly recognize what to do.... . It got 3 codes in check engine light stating:
1. multiple cylinder misfire; 2. Crankshaft reference 18x circuit malfunctioning; 3. Low EGR flow detected; and suggested to Replace ignition coil. . I was thinking to replace crankshaft positioning sensor. My problem can be solved by replacing it? Please suggest me.. what to do?

My car has 207000 miles.
My car has an automatic transmission.

A: Hi there. It sounds like there is water in ...

Hi there. It sounds like there is water in a connector, such as the crankshaft position sensor. Before replacing this sensor, remove the connector and check for contamination. The contamination could be soapy water, oil, dirt, or any combination of water and something else. When this occurs, there could be an intermittent open or short occurring intermittently creating the erratic engine operation.Thoroughly clean with brake cleaner and dry the sensor and wire harness connector. Clear the codes and recheck the engine operation and codes. If the problem persists and the code returns, have a qualified technician perform an inspection to determine the specific cause of the concern and avoid replacing unnecessary parts. Your Mechanic has several available technicians that can assist you with a check engine light inspection.

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