So I replaced my spark plugs last week. I "upgraded" the from the Bosch Platinum Single 'electrode' to the Bosch Platinum +3 (3 electrodes) thinking this might provide a few extra ponies. To my surprise, I think this may have actually hindered my case more than anything. I'm strongly considering removing the +3 Platinum's because there seems to be a bit of surging/power loss in the mid-RPM range. Any suggestions on what plug to put in?

 

Get the platinum plugs out of there and put in the stock bosch or ngk copper single electrode plug. Platinums do not work well in these cars.