i have plat +4 in my 93 vulcan and i have been getting terrible gas mileage. 200 miles per tank. does anyone know if they could be the problem? if so what are the best spark plugs to get for my engine. thank you
Motorcraft copper core. Platinum is not as good a conductor of electricity as copper is. A lot of people think platinum is better when they actually are not. The only advantage you get from platinum is that since it is a more durable material it can last longer, 100K versus the 30K of a copper core plug.
Also don't let anyone tell you that Autolite is the same as motorcraft. Motorcraft are the original plugs and autolites are made based off the motorcraft specs. I'm sure they are very similar but they are not the same. I was told along time ago that they came of the same line and that was a big fat lie.
Alot of people have been complaining recently about the Bosch +2's and +4's. I would go with either morotcraft of Champion plugs. I would also agree with Hightechredneck about copper core plugs, especially on a vulcan which is known for detonation problems.
When I had my '00 Vulcan ranger, I ran non-platinum autolite plugs that were meant for the thunderbird SC. They are a little cooler plug, and it helped gas mileage as well as got rid of some detonation.