[The Atomic Ass]

So, no tank report I take it? How about ambient conditions, cold, warm? The factory instrumentation in my fathers Bravada is over 2mpg off at all times.

Perhaps both were in poor states of tune, or had poor factory tuning?

Another is inexplicable, but some cars do acclimate themselves to their normal drivers, (this is not a computer phenomenon), and will continue to act as if that person is driving long after, as much as 6 months. One of the cars my father owned, he bought from my grandfather, (and this was a carb, non-computer car), and for 6 months after that, it continued to drive like my grandfather. Surge forward, fall back, surge forward, fall back...

Just tossing ideas out there...