Got a couple more mileage tests to report. After disconnecting the battery to clear the engine codes, we drove on the highway about 160 miles. First test with the DE device turned down to 10% was <b>23.4</b> mpg, turning it up to 15% got <b>18.9</b> mpg. Both were with the HHO generator on and connected to the engine. This is very exciting, since the best hwy mileage we've ever achieved was 16.8 mpg before installing the kit. This is also a big jump from the previous test run at 16.1 mpg. No engine codes or CEL/SES light ever came on like it did on the leaner setting of 60%.