Many thanks for all the info! Everybody's response has been a great help. However, I'd also like to know what do the acronyms EOC and DFCO mean. Also, it may be awhile but rest assured I will post my results after I've used the ScanGuage awhile. Again, thanks...what a great site!!
the first is self explanitory. the second, for most new cars, occurs when you coast engine on in gear above 1k rpms. at 1k rpm, DCFO ends to maintain idle. so, coasting in gear allows little or no fuel usage.
You can't DFCO and be in neutral. DFCO requires the engine to be turned by the road so that no gas is required to keep the engine running. DFCO happens with the vehicle in gear, rolling, above 1000rpm, and your foot entirely off the gas pedal (and may not always happen even under those conditions, and there may be a delay before it starts).
i use DFCO and neutral coasting depending on application...
when driving around town(back roads) at lower speeds and rpm, i use neutral coasting because it enables me to glide a greater distance and because DFCO would end quickly in gear. this application is a low(sometimes zero) traffic one.
on the highway, at higher speeds and rpm, i use DFCO as the rpms take longer to drop to 1K. i use it on hills, off/on ramps, and approaching red lights.
concerned about ignition wear, i've only been using EOC to end a trip. there are long, low traffic situations both getting to work and home providing great EOC opportunities.
More thanks for some good information and furthering my continuing education about such matters. Here's another request; which method, as mentioned by bowtieguy in his first two paragraphs, has the biggest effect on saving fuel?
It really depends on a lot of factors, and the best way to find out what works for you is to experiment. Here's a few guidelines:
If you intend to slow/stop, as when the speed limit lowers, you approach a stop sign/red light, or you gather speed down a steep hill, you should DFCO.
If you don't plan on losing any speed, you should neutral coast, or if you're comfortable with it and your car is ok with it, you could EOC.
Keep in mind that you need to study your car's DFCO behavior before being sure it works when you expect. There are requirements for speed, RPM, accessory usage, what your most recent actions were (accelerate/cruise/shift/whatever), if the engine is fully warmed up, and so on...and then there could still be a delay before it will DFCO, which would make short DFCOs counterproductive.