I spoke to the mechanic that performed the compression and leak down test. He indicated that cylinder #6 had low compression compared to the other cylinders. The leak down test reading was over 30% in cylinder #6 and indicated both a leak in the intake and exhaust valve. The plugs are not fouled and no blue smoke comes out of the tailpipe.

Also, I found spark plugs in the trunk of the car and I am thinking about replacing the plugs. I found Bosch Platinum +4 spark plugs and NGK V-Power Copper Resistor type. Which type are better plugs? Thanks.