Does racing the engine burn more gas?

Momentum and stuff still turning needs no explanation. You posted earlier that somehow the motor turns off the injectors. If the injectors are off when you aren't pushing the gas pedal, how would it idle? Injectors turned off means the motor has no gas to burn. Yes, the momentum of the moving vehcile will spin the motor tranny and rear wheels whther the key is off or on.

 

from what i have heard and noticed, it doesnt turn all the injectors off but instead a few

 

Cutting them back to idle is one thing and turning them off is another. Cutting them back to idle flow when coasting in gear makes complete sense, turning them off and the motor staying running or idling does not.

 

shutting off a few injectors wouldnt do anything except stop those cylinders from exploding, thus the engine can slow down the trans/wheels

 

It might be variable valve timing but I doubt we have variable cylinder motors. If odd cylinders aren't getting gas for whatever reason, how is the motor gonna act normal? How would it not be throwing CEL for cyl X lean on bank X codes.

 

Please, I have done both many times, the momentum issue is no mystery. It keeps it turning, sure, but if the motor is not running then your gonna slow down a whole lot quicker and it won't be all normal feeling.

 

... what he said.

 

Again, the motor will turn with momentum alone or by hand, of course. I know the thing isn't gonna lock up and skid tires and throw you thru the windshield just because the motor stops running while your moving, of course it won't. If you coast downhill with the motor off in gear will feel a lot different than coasting downhill with it in gear with the motor idling without your foot on the gas. Call me old school but if the motor isn't getting at least idle pressure from the injectors then it doesn't make sense to me that these touchy ecu driven things are gonna like that and not throw codes and "run" like crap or die.

 

brake pads are less expensive then transmission. i got an ultra gauge and it goes into open loop when i slow in gear so i dont do it because 1. i try to stay in closed loop all the time and 2. brakes are cheaper

 

irregardless brake pads are cheaper than clutches and transmissions... if you're engine braking in traffic on flat ground than you are wearing the tranny for no reason.

 

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I usually use the engine to brake during everyday driving. Downshifting all the way to L. I find i drive a quite a bit more defensively as well give myself more room to slowdown take a little bit longer to stop instead of speeding up to the light and hammering on the brakes. Milage is better as well. When i drove like and idiot I used 17L/100km (13ish mpg) now i usually get 12-13L/100km (19.5ish-18mpg). This is all city driving but mind you not a ton of rush hour.

 

I realize brake pads are cheaper but my manual does have a whole chapter on downshifting to brake with the engine. Auto tranny BTW