Alright I admittedly do not know much about cars and so if you would like to laugh at my question please feel free but when you are done with that I was hoping you could answer it for me.

I just bought a 2000 Civic Ex automatic and noticed that I have two options for Drive. D3 and D4, Assuming that means Drive 3 speed and Drive 4 speed. My question is does using D3 in the city get me better MPG or does it not matter? And what is the purpose of having the two options?

Thanks in advance.

 

D3 locks you into 3rd gear as your highest gear, ie, the automatic can only select between 1, 2, or 3.

D4 lets your car choose any gear, 1, 2, 3, or 4 (in the auto there is no 5th gear like in a standard...)

Youd get better mileage by just putting it in D4 so when youre going a bit faster the engine can put you in 4th gear and wont have to work as hard, ie revs can drop...so if youre going 3000 in 3rd, maybe thats 2300 in 4th (or something like that)...

D3 is if you are going up and down a lot hills, or you want extra push to power over things, or you want the engine in a lower gear...Also in D3 the car wont have to hunt between D4 and D3...some people find that annoying in autos...

 

most people lock it in d3 in towns and cities from what I've seen. I only put my car in D4 if I know I'm going to be going faster than 30mph. Any slower and the car won't go into 4th anyway. (I get bored when I'm driving and notice weird things. Like the car will shift into second as soon as you let off the throttle just a little bit when the car starts moving. And that it shifts into 3rd at no slower than 25. And that it shifts into 4th at no slower than 30 lol)

 

That auto is a 4spd overdrive tranny. Overdrive (OD or D4)gives you lower revs for better MPG...and higher top speed at redline. I always drive in OD unless I'm using engine-braking in the mtns or towing a trailer. Using D3 when you don't have to will rev out your motor unnecessarily. The car is meant to be allowed to shift through all forward gears under normal operation. That is why D4 is illuminated in green and the other ranges are red. Read your manual.

Would you generally drive a manual in a low gear at high RPMs if you wanted MPG? No. An auto tranny will generally select a lower gear if it needs one going uphill or on flat ground.

 

It's a good thing to have for snow and ice conditions. Like going down hills and you want the engine to brake you instead of the brakes (in which case you would slide and skid). Or like stated above with towing etc.

 

from experiance i would not shift an automatic just because thats how i blew my tranny. but if your in the snow it wouldnt be a bad idea to downshift it instead of brakes and possibly sliding.