I only have experience in modern years with TT chips..make that recent years LOL
but, they kick out of the cruise mode when the lv8 rises to a certain level. Therefore, if you live in hilly country, the lv8 will rise every time you start up an incline and the car will go for a richer number. In other words, the best gas mileage comes where there are few changes in incline.
I used to set my cruise where the oem O2 read a steady 000 on the scanmaster. This was close to 17-1 on the wb. When I went to 75# injectors, I came down a bit for fear that the larger injectors might be a bit erratic and low pulse widths and I might have a problem.
In the early days of the MaxEffort, I used to keep removing fuel until I could feel a skip in the engine at 75 mph, then I would add a couple percent back in and call it good. That always read 000 on the sm.
Pretty soon, someone will come in and inform us that setting the a/f to stochiometric gives the best mileage but I am calling bs in advance of that.
