2006 Audi A4 2.0 T shutter. What causes my plugs to go bad ?
Car bought used for my son. The car has less than 80,000 miles on motor. New
belt installed at 75,000 miles. It had loss of power intermiting had plugs repaced
. All was well for 1000 miles now its back again. What can be causing the plugs
to fail? No smoke on accelaration?