Scangauge II current trip MPG reading too high?

[ExtremeTDI]

I just took a road trip from Dallas TX to Orlando FL. During the trip I had an awesome 850+ mile tank. Now that I'm home, I'm noticing that my current trip mileage is going a little crazy. My instantaneous reading seems normal, but when I check the current trip number it seems anywhere from 15 to 20 mpg too high. The current tank mpg seems ok as well. Before I left for Florida I was averaging mid to upper 50's for my 20 mile commute to work. Yesterday, the scangauge ready 68.3 on the way to work and 73 for the trip home. Has anyone seen this issue before? I didn't change any of the settings during the trip to Florida. Also, I'm getting negative mileage periodically when coasting in gear. This is a new issue as well. I appreciate any feedback I can get.

Thanks

 

[CentralFloridaTDIguy]

vehicle details

what year, transmission etc do you have for your car?

 

[ExtremeTDI]

My car is a 2000 Jetta Tdi with a 5 speed. The car is totally stock other than the SGII. The really odd thing is that after making my commute first thing in the morning the "current trip mpg" is 10-20 mpg higher than my "today trip mpg." They should be the same since it is the first trip of the day, and before last week I believe it was. The speed matches my GPS and the rpms seem match the dash pretty closely.

 

[tttthumper]

As per the manual.
The current mode resets itself after 3 minutes being turned off.
The today stats, get switched to previous days after 8-10 hours being turned off.
If you drive at after 10pm at night and then drive at 6am in the morning. SG might still thinks it's a current day(just a thought)

Negative mileage while coasting in gear. I would unplug it and re-calibrate it and see if the problem happens again.

 

[ExtremeTDI]

I understand that the current day goes to previous day after a given amount of time. The issue is that the current trip mpg is dramatically higher than the daily trip mpg. Anyone know what would cause this? Is a sensor in the car failing?

 

[no_one_of_consequence]

IMO SG behaves erratic when changing the units (L, gal, miles, km) or when disconnecting the unit. Verify your configuration maybe something was changed.

 

[K5ING]

How long are your "current" trips and what kind of driving is it? If it's only a few miles, I can see where it would be skewed one way or the other. As long as your daily and tank averages are looking normal, I wouldn't worry about it.

 

[ExtremeTDI]

My commute to work is just over 20 miles each way. And before my vacation to Florida last week the SG was not acting this way. That's what is puzzling me. What has changed. I did check the units and everything was just as I had set it up originally.