99.9 MPG...Possible?
Thread Starter
Senior Member
Joined: 01-20-2006
Posts: 1,230
From: Dallas, TX
99.9 MPG...Possible?
Ok. You're not going to believe this. I sure didn't. CJ achieved 99.9 MPG during his trip to FL. I needed proof. He has video to prove it. I had to test his theory, and by George, I achieved it too! It was amazing! CJ will be back home from FL later this afternoon. I'll let him explain the details on how this was achieved. Stay tuned... 
New Member
Joined: 05-10-2006
Posts: 14
From: Hawaii
To get the gauges to show 99.9 MPG. That is no big deal. Just get on a long downhill don't step on the gas pedal and reset the guage.
The real question is how long did you maintain the 99.9 MPG once you stopped going down hill.
The real question is how long did you maintain the 99.9 MPG once you stopped going down hill.
Senior Member
Joined: 01-21-2006
Posts: 120
From: United States
Originally Posted by txsman2930
Ok. You're not going to believe this. I sure didn't. CJ achieved 99.9 MPG during his trip to FL. I needed proof. He has video to prove it. I had to test his theory, and by George, I achieved it too! It was amazing! CJ will be back home from FL later this afternoon. I'll let him explain the details on how this was achieved. Stay tuned...
I've seen it too.
Anyway, off on my own road trip now. Bye...
Senior Member
Joined: 10-14-2005
Posts: 5,359
From: SoCal
The computer calculates mileage based on current speed, average speed, distance traveled, throttle position, and TIME since the last reset.
Based on those factors, you can easily see why it will read 99.9 (it's numerical limit), when resetting the DIC while going downhill at say 65mph with your foot off the gas.
This also explains why the DIC goes "crazy" after a reset at highway speeds. It is simply trying to play "catch up" with all the data that is rapidly changing (distance traveled, averaging the speed against time since reset, and averaging the mileage). If it didn't change quickly it wouldn't be very accurate.
I have done the math on several tanks of gas and found the DIC to be extremely accurate regarding mileage. Looks like GM really did their homework on this one!
Based on those factors, you can easily see why it will read 99.9 (it's numerical limit), when resetting the DIC while going downhill at say 65mph with your foot off the gas.
This also explains why the DIC goes "crazy" after a reset at highway speeds. It is simply trying to play "catch up" with all the data that is rapidly changing (distance traveled, averaging the speed against time since reset, and averaging the mileage). If it didn't change quickly it wouldn't be very accurate.
I have done the math on several tanks of gas and found the DIC to be extremely accurate regarding mileage. Looks like GM really did their homework on this one!
