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t vago · 11-03-2011, 07:53 PM

I have been able to verify that it is possible to pulse and glide with an automatic transmission. There is no need to shift to neutral, or do any sort of hardware modifications to your car. I've done this myself with my truck.

The idea is, once you're at speed, try to briskly accelerate to a few miles above your desired speed, then let off the gas to allow your vehicle to slow down to a few miles below your speed. Then, accelerate to go to a few miles above your speed, and so on and so on...

If you accelerate and you find that your vehicle downshifts on you, you're using too much gas. Back off a little on the gas pedal, and try again. Also, if you have access to something like a ScanGauge, and you find that your ScanGague is telling you that your vehicle goes into open loop when you accelerate, you're using too much gas. If you use your brakes, well... that should be obvious that you just converted some gasoline into brake dust.

I've discovered this method on my daily commute to work, where I would oftentimes be caught in heavy (but still moving) traffic. I used to wonder why I'd get as much as 8% better fuel economy on days that I'd have to deal with heavy traffic, than on days where traffic was relatively light. In either case, my travelling speed was not a contributor to increased FE. Heavy traffic on my commute typically travels about 8 over the speed limit, and I normally aim for 7 over.

I first noticed this by noting total trip fuel consumption as measured on my Scangauge II at mile 25 of my commute into work. On heavy traffic days, I have observed as much as 21.2 and usually around 20.5 MPG. On light traffic days, I have observed around 19.4 to 19.6 MPG this past month. I have subsequently tested my "P&G" theory this past Sunday (a guaranteed light traffic day on my commute into work, thus no possibility of "drafting" to explain my FE gain, and no possibility of annoying somebody behind me), and got 20.9 MPG.

So, yes, it is possible to P&G with an automatic. It's just different than for a manual.

11-03-2011, 07:53 PM	#6 (permalink)
t vago MPGuino Supporter Join Date: Oct 2010 Location: Hungary Posts: 1,807 iNXS - '10 Opel Zafira 111 Anniversary Suzi - '02 Suzuki Swift GL Thanks: 828 Thanked 708 Times in 456 Posts	I have been able to verify that it is possible to pulse and glide with an automatic transmission. There is no need to shift to neutral, or do any sort of hardware modifications to your car. I've done this myself with my truck. The idea is, once you're at speed, try to briskly accelerate to a few miles above your desired speed, then let off the gas to allow your vehicle to slow down to a few miles below your speed. Then, accelerate to go to a few miles above your speed, and so on and so on... If you accelerate and you find that your vehicle downshifts on you, you're using too much gas. Back off a little on the gas pedal, and try again. Also, if you have access to something like a ScanGauge, and you find that your ScanGague is telling you that your vehicle goes into open loop when you accelerate, you're using too much gas. If you use your brakes, well... that should be obvious that you just converted some gasoline into brake dust. I've discovered this method on my daily commute to work, where I would oftentimes be caught in heavy (but still moving) traffic. I used to wonder why I'd get as much as 8% better fuel economy on days that I'd have to deal with heavy traffic, than on days where traffic was relatively light. In either case, my travelling speed was not a contributor to increased FE. Heavy traffic on my commute typically travels about 8 over the speed limit, and I normally aim for 7 over. I first noticed this by noting total trip fuel consumption as measured on my Scangauge II at mile 25 of my commute into work. On heavy traffic days, I have observed as much as 21.2 and usually around 20.5 MPG. On light traffic days, I have observed around 19.4 to 19.6 MPG this past month. I have subsequently tested my "P&G" theory this past Sunday (a guaranteed light traffic day on my commute into work, thus no possibility of "drafting" to explain my FE gain, and no possibility of annoying somebody behind me), and got 20.9 MPG. So, yes, it is possible to P&G with an automatic. It's just different than for a manual. Last edited by t vago; 11-03-2011 at 08:01 PM..