I'm guessing this may have been discussed earlier, but I've not been able to find it anywhere. I have a new '06 HCH and notice that occasionally while I am going downhill with my foot off the accelerator the MPG drops way down, showing only one bar. When that happens if I just tap the accelerator it gets back to rights, but I'm curious if anyone knows what is going on when this happens.

 

it's being said that it's a "calibration" issue. it happens to me also. not very often thou. the fe is not dropping... it's just a display problem

 

I have seen this also. Not all the time but enough that I had wondered what the heck was going on.

 

I hadn't seen this in the first three months I had the car, and believe me I watch that gauge constantly. In the last week or so I've seen it several times. I don't like it.

Also note that if you're coasting with the MPG gauge at 100 and you slow down to less than about 20 MPH the engine does kick back on and begin to consume fuel. Apparently the car is no longer moving fast enough to keep the engine rotating at enough RPMs, or whatever...