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I have a 2008 Audi A4 2.0T. I have lately been using the Pulse and Glide method to increase my mpg. However when I go into my glide and put the car into neutral the built in mpg gauge does turn to "- - -" which is "infinite". It does do that when I'm in Drive and just let completely off the throttle. When I go into neutral the MPG just goes much higher, usually arround 80-150 mpg. The reason for my concern is it wouldn't be quite accurate because it doesn't affect the average mpg as well as "- - -" or infinite. Anyone know of a way around this? Would a separate MPG tracker work better? Thank you in advanced.

What is happening is that your car is gong into "deceleration - fuel cut off " or DFCO. When you take your foot off the gas in drive, the engine shuts off the fuel injectors and continues to turn the engine through the drivetrain, thus allowing you to slow down and save gas doing so without idling. That's when you see the " - - - " on your iFCD. When the car is in neutral, the injectors are still spraying, but the car won't slow down as fast, and coasts much further. This is generally to your advantage if you aren't necessarily trying to slow down.

A Scangauge or similar device will be more useful and robust than what you are using, but it will display similarly when this happens.

My car will sometimes display '---' when coasting in neutral even though it's actually burning fuel. It just does this instead of displaying a really high number. It is still keeping track and calculating correctly, it just doesn't show you the information. If you switch to L/100km you will see this. The only time it will go down to 0L/100km is when in DFCO.

Thanks a lot for the information. That makes sense. Another question, would it be more fuel efficient to go into neutral or stay in drive then?

It all depends, I'm finding coasting in N is getting better MPG than DFCO but I still use it slowing down to traffic lights or stopping me from going too fast down hills. Obviously FAS will give you the best mpg but it's not always appropriate!

frv is correct.

Is the A4 a car that can be glided in neutral without damaging the transmission?

I would assume it is ok to coast in neutral. Most newer cars can do this just fine. Plus the one I drive is CVT (continuously variable transmission). I find I hardly ever go over 2000 rpm. Usually it stays at 12-1500 rpm when in drive and 800 when in neutral. So when going from neutral to drive it is only going from 800-1200 rpm which isn't to hard on the tranny. So I think it should be ok.