It sounds like your mechanic doesn't really know what the problem is so just starts throwing parts at it with the hopes he guesses correctly sooner or later and the problem goes away.
That's why I quit trying to self diagnose cars years ago, I'd have a slight miss so I'd change plugs, then points, then cap and wires, then fuel filter, then this, then that and on and on which seldom fixed the problem but always costs lots of money and time by the time I was done.
I finally found a good mechanic and let him do his experienced thing and I'd work a Saturday to pay for it and take Sunday off instead of working again on my car like I had for the last several prior weekends.
Find a different mechanic.
That's why I quit trying to self diagnose cars years ago, I'd have a slight miss so I'd change plugs, then points, then cap and wires, then fuel filter, then this, then that and on and on which seldom fixed the problem but always costs lots of money and time by the time I was done.
I finally found a good mechanic and let him do his experienced thing and I'd work a Saturday to pay for it and take Sunday off instead of working again on my car like I had for the last several prior weekends.
Find a different mechanic.
