took my car in on july 4th weekend - the autoshop ran a diagnostic and found that the number 5 cylinder was not firing. when they looked into it they found that the gasket was leaking oil into the sparkplugs and caused that coil to go bad. The cost for replacement and labor was about $740.00 (included new spark plugs because they were ready for replacement anyways, the gasket, coil, labor) - the mechanic said it might be a good idea to replace the other 2 coils on that side of the engine because of the labor involved on taking everything apart to reach them if one went bad. i went ahead and played it safe and had them replaced which added an additional $380.00 to the price. the endeavor is running fine now.
question? was replacing the other 2 coils a good idea?