I don't think you need an overhaul on the engine yet. How many miles do you have on the engine? What did the mechanic say when you went pick up the car besides #6 plug was dead? Did he do anything else? It seems like the first order of thing is to find a knowledgeable mechanic to work on your car.

I am not a mechanic and not pretending to be one, but you may want to start looking for the obvious first if you have not done so. I will make sure all the plug wire are good, replace them all if they have been in the car for a long time. Check and replace any ignition related items if they are in the car long time. Check your OVP relay while you at it. Check your fuel filter and replace if needed.

Remember, your car is about ten years old and some of the items I mentioned may need replacement.

Do a search in the forum and you may come up with more ideas. Good luck.

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95 R129
04 Infiniti G35.5 BS
10 X204