Remember that our car shuts down 3 of the 4 cylinders when it hits that 100+ mpg readout and although this is run by the third cam profile I'm sure it does take just a bit of time for the car to note this through the gauges. I have also had this happen to me - middle of gliding, while accelerating slowly (mph readout climbing) and IMA bars showing charge, descending a hill with constant throttle, etc. I dont' think it is an issue and cure it simply by applying or lifting the throttle slightly. I just chalk it up as one computer telling another what it is doing but not telling the third, etc. No issue I bet.

 

I don't think it shuts down 3 of the 4 cylinders. I believe it engages a round cam lobe on all 4 cylinders. If one kept running you would eventually see unequal wear which would make one cylinder eventually produce less power than the others. This would in-turn place an unbalance of torque on the crank shaft. This seems like it couldn't be possible.
However, I am known to be wrong and Honda is known to surprise me.

 

I also do not think it shuts down 3 of 4 cylinders, but if somebody has a good reference, please post it. As for the wear, I do not know if this is an issue. Honda shuts down 3 of 6 cylinders in their VCM (variable cylinder management) engines. Here is a very descriptive movie about how the engine works in the current generation Honda Civic Hybrid. It's worth watching if you have not seen it.
http://world.honda.com/HDTV/news/200...05b/index.html

 

with 3 of 6 your eliminating every other cylinder or 1/2 of the cylinders on a bank. the torque discrepancies probably wouldn't be the same.

 

Here is the link from Honda.com noting this for you. Like I said, these cars are REALLY phenomenal in all of their Engineering - it just astounds me sometimes. In another Technical Manual that I have it puts this in other terms, "[The] VTEC system disconnects all valve lift on cylinders 2, 3, and 4. On deceleration the PCM grounds the VTEC solenoid and oil pressure deactivates 3 cylinders. This helps recharge the main battery pack gaster in traffic." This conflicts the Honda.com post that says it shuts down all cylinders but nevertheless it is a fantastic design.

 

thats interesting, so basically it runs as a 1 cylinder generator when its recharging at idle with no propulsion load?

does anyone have a PDF of the tech manual on the 06 or 07 manual? like the Helm manual?

 

Actually, the '06+ models cut off ALL cylinders, so that no air is being pumped in/out of the motor which in turns gives a 10% increase in available energy to be used by the regen system. This IMO is the most amazing thing about the engine....how the valves can be tightly closed with the pistons still moving. It has really stumped a lot of car savvy people that I know including my father and our mechanic/friend.

 

I've noticed this weirdness in the gauge several times in the past day or two. It sure didn't feel like anything would be causing the decline (engine reving, etc.) so I figured it was just a brainfart from the computer. It doesn't sound like it's a problematic thing, but I'll subscribe to this thread to keep an eye on it.