ok you know when youre about to slow down for a light or turn or whatever and you downshift and let the clutch out to slow you down and what not? does that waste any fuel? because the engine revs so is that using any fuel? or no? or is this a dumb question?

 

I think its just a dumb question. J/K

Well I dont think it would cause you are not asking the engine to move.

 

NO question is a dumb question. Yes I believe that it would waste FUEL!

 

its the same as if you were accelerating at the same rpm in the same gear so it is still using gas as for actually wasting gas im sure its minimal so i wouldnt worry about it.

 

but how does it waste gas if im not pushing on the accelerator to make it inject fuel?

 

its still getting fuel.. the thing needs gas all the time just depends on what its doing as to how much is uses.

 

it all depends.. some ECUs have a fuel cut so you arent wasting fuel while compression braking while others still spray.. but its not a huge waste..

 

What little gas you did waste would be made up for by saving brake wear. Plus brake dust just looks icky.

 

it uses fuel if the rpms rise..if I went under your hood and cranked your throttle body...you wouldnt push the gas....

 

Keep in mind that the tranny is raising the rpm rather than the pistons so naturally youre going to spend less energy doing so and use less fuel. But theres really no such thing as fully closed throttle your car would stall if there was.