Driving Tips To Save Gas [3]

When driving in the city I have found that when a light turn red a good distance ahead of me, I take my foot off the pedel and let car coast to the light or stop sign. You would be suprise to notice how much it seem you yet have your foot on the pedel unless you're going up a hill. matthew wright | Jul 30, 06 | 9:57 am

I have questions regarding more advanced driving tips to save gas.
* I know some people who step on the gas for a second or so, and then let it idle for the next 2 seconds or so. While I believe they do so to prevent their feet from getting tired, I would expect the best gas milage with as few changes as possible to the gas pedal. Or does it also depend on the car (see next question)?
* Some newer cars display the gas milage while you drive. I noticed that when I took my foot of the gas while going downhill, it actually claimed it wasn't using any gas. It was a manual car and when I pressed down the clutch, it would show a value again. I thought this was not correct until someone told me that newer cars switch of the gas when you take your foot of the gas and are going above a certain speed or rpm. I guess this means the engine valves would have to open up, right?
* On a car like this, I assume it can still pay of to switch into neutral on a downhill stretch: While in neutral, you still gas to maintain the engine idle, but you also avoid the engine break and pick up more momentum for the uphill, right? Of course, instead of breaking, engaging the engine would be safer and more efficient.
* How is that on a car which does not turn off the gas? Do higher revs going downhill also mean a higher idle gas consumption?
* At what point does it usually pay of to turn of the engine in idle? I believe starting up the car takes more gas then idle? How about stopping for 3 seconds to let a passenger get off? 10 seconds to look at a map? 30 seconds to make a phone call?
* About the cruise control: While I sometimes use it to let my foot rest, I actually don't like to use it on most highways unless there are no hills. On a car with a small engine, it maintains the speed of the car on an uphill. This often causes the car to push hard on the gas, switch into lower gears and rev high. Then, on the downhill, the idle basically is an engine break. When driving, I slow down enough on the uphill to stay in the highest gear unless I start slowing down traffic. On the downhill, I find just a little bit of gas will help me build up some momentum with very little use of gas. I feel that can easily beat the cruise controll and minimize wear on the engine. Do you agree (while of course safe driving must be maintained)?
* What actually is the rule for best gas milage? Is it really the constant speed of 55? Or is it a constant ideal rpm of maybe 2000? or whatever the engine is optimized for? together with the highest/overdrive gear?

Where can I find more information on efficient driving? Thanks for taking the time for all my questions? jack black | Dec 03, 07 | 2:36 pm