Cadillac Repair: problems with odometer, gas gage, basic consule, volt ohm meter, digital speedometer

Question
I'm having a problem with my consule the odometer reads 40mpg more than what the cars traveling, all  had a console black out for 5minutes at one time, gas gage fluxuates occasionally, haven't been able to figure out what the problem is.

Answer
I need the YEAR and MODEL of the vehicle and I also need to know if you have an ANALOG or DIGITAL speedometer. What we need to do is perform some simple test procedures using a DIGITAL VOLT/OHM meter which you can purchase most anywhere for about $15.00. Once you get your meter, E-mail: onlineautohelp@msn.com