@haseebhamid thank you for posting a detailed inspection of your problem but the hit and trial method is how your mechanic gains his knowledge so...better find a better mechanic(impossible task).
What is your car's mileage?
I wonder whether the timing chain gets loose on its own or is it part of some routine maintenance to check its tension?
I suggest you check timing via the scanner and if . post a graph of timing vs rpm.
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