GMC YUKON ENGINE POOR MILEAGE

A Short While Ago I Ran A Fuel Injector Treatment Through My Fuel System With A Full Tank Of Gas According To The Treatment Instructions....

Sucking Up Gas Like Crazy.

I'm Having Problems With Engine Power And Fuel Consumption On My 95 Yukon 5.7l. It Starts Fine. Idles Fine. But When I'm On The Hwy Or Going...