Today's gas is pretty clean I think because all the cars have fuel injection.. so does a fuel injection cleaner really help ? If so... witch one to buy... thanks... richard

Today's gas is not clean. In fact, the regular gas is much, much more full of sludge than it was just 10 years ago. Any small engine repair person will tell you to only use Premium gas in 2-cycle engines, like lawn mowers, chain saws, etc. I stopped using Regular in mine 4 years ago, and now the carburators never clog up. They were needing repair about every 4 months with Regular gas.
Fuel injection cars don't really need clean gas, cause there are no small carburator jets to clog up. My mechanic friend told me to use a Fuel Injector cleaner every 3 or 4 months, and it would help keep the injectors clean. Any brand is good, and usually made of the same ingredients.

Thanks...

Chevron's Techron and Shell's Regane are two excellent products. I add these to a tank of gas every 4,000 miles.