For quite sometime a few years ago,Bosch would put their platinum junk on promotion.and "do it your self" places would make extra money by pushing the customer,who,like the counter kid,didn't have a clue about things like heat range.As a professional mechanic,I've pulled out many sets of that junk,replacing them with the recommended spark plug by the engine manufacturer,many had burned up in as little as 6,000 miles.My late brother called me one day about a friends v6 Mustang that they couldnt get to run right.When I asked the owner,who I also knew,what plug he put in the engine,his responce was Bosch Platinum's,the guy at Autozone said "these are the "top Sh!t"My responce was,he called that right,they are indeed sh!t,go get the Motorcraft or Autolight recommended replacement plug and install them.They did,the misfire went away,the check engine light quit flashing,and the car run fine .Their reputation is so bad now that even the know little people at places like Autozone and Advance wont recommend them. For your W engine use the A-C Delco,Autolite,or NGK plug,and get the correct heat range for your level of build,and intended driving use,and you'll be happy and trouble free.