just a thought, I work on the TBI units and sell kits. is it possible that your fuel pressure has dropped to the point that its making it hard on fuel? you should be getting 20+ MPG
With a granny 4 speed and 360?! i wosh i got that milage! I don't honestly know. All I can spell is fuel in the exhaust. Octane fumes would kill me before canon monoxide would
I'm getting 10hwy mpg on a good day and 6.8mpg town...
