Hello all, I have checked several IPhone and Android apps, not very practical for me. However, I downloaded and have been testing a very useful and amazing IPhone application, which has a free versión and updates for more information. It outstands among the lot of fuel economy apps available. Haven't seen other of this kind. The application gives fuel economy of the car without any connection to it, just based on the horizontal and vertical movement of the car, acceleration and car specs like weight and engine size. Besides, the App uploads (optionally) yr performance to its web site, where all journeys info are saved and where driver can review them anytime. Main strenghtness of the App are: You can use it with gasoline an diesel cars. It gives you advice as how to save fuel, and counts $ saved in yr journeys. It graphs your driving efficiency in terms of MPG, CO2 emission, brake use, etc. You can use it on old cars without the OBDII standars. You can test your fuel economy mods using this application. The App makes very good use of physics and of the info of the built in GPS of the phone. The optional real time fuel economy indicator is very useful to guide you on driving efficiently. Weakness: You cannot get the application working for a complete tank of fuel, for validation and callibration purposes. At its present stage, only it only gives results of single journeys. DriveGain doesn´t overestimate fuel economy, it is more to the opposite side. In my test of a complete tank of fuel, DriveGain understimate my fuel economy by 10% approximately. OldBeaver Site: www.drivegain.com By the way I am using this application in my 1993 Mercedes Benz 300D turbo. I ask forum members to test the application, share results and send feedback and suggestions to the authors, in order to improve it.