Mileage Shop Hydrogen on Demand / Generators Internet

 I placed an online order with Mileage Shop on 04/01/2012 for (1) one of their Hydrogen on Demand generators.  I received it within a reasonable time and proceeded to install it on my vehicle.  I own a 1996 Jeep Cherokee XJ with the 4.0L EFI engine.  I was presently getting on the average of 15-16 mpg combined city/highway.  I was led to believe by the sales representative that I could expect at the least a 45% - 60% increase in mileage after installing the HHO generator.  I continued to call back the Tech Support  (6-8 times in the last two months)  after the  initial 1000 mile break-in period.  But after the  1000 mile break-in period / initial flush of the unit I started to asking for what he would suggest me to do to increase my MPG's. We proceeded to  start increasing at 5 Amps and increased the Amps by increments of 5 amps at a time until we reached the maximum of 15 Amps. looking for that "sweet spot " that they spoke of where I would get the increase in MPG's. i was told to not exceed 20 Amps because it would create Steam, and defeat the purpose of increased MPG's.  I requested an e-mail address of someone who had a vehicle similair to my vehicle so I could correspond with them to see how  " they " corrected their problem with the performance of the generator, BUT was not given that information.  I have put over 3000 miles (10) TEN - 20 gal tanks of gas ) in this vehicle after purchasing this HHO generator with absolutely  " No Substantal " increase in MPG's what so ever.   I would not recommend a person to consider the purchasing this product.  I don't feel that I'm the only person that has encountered this problem with the Mileage Shop.