I usually donâ??t answer fuel mileage questions butâ?¦
(I assume you have a V6 and a manual)
The V6 cars were only rated at 28-29MPG hwy at 55MPH under ideal conditions. Given the age of your vehicle and mods your actual MPG (at 55) would be a little less. At 80 or 83 MPH it would be a lot less. I would expect about 20-23 MPH at these speeds. How did you record 30 MPG at 80 MPH??? It could be as simple as the pump shut off before the tank was full. This would also explain the drop to 20 MPG on the next tank.
When I drive at speeds over 70 MPH I get about 21 MPG. When I keep it under 70 and go a little easy in stop and go, I get 25 with the AC off 23 with it on. V6 ATX 90k mi well maintained. It has never exceeded 25 MPG.
jeff
