Poor Gas Mileage 3.8

[Marty85]

The PCV valve on the 3.8's is located beneath a cover with 2 10mm bolts on the top of the intake manifold towards the front on the passenger side. Take the cover off you and you will be able to reach the pcv valve.

[JoeyPro]

14.8 mpg last time I filled up... Im never even heavy on the gas...

Everything runs fine, except I notice that taking off is a lot smoother with a full tank. I dont know if that is all cars or what.

Im going to replace the PCV valve. But since changing the fuel filter will be a pain in the *** I am goin to eat until I take it in to get the oil changed then have them change it.

Is there anyway to test if the o2 sensors are bad? I dont want to waste money replacing things that are working fine.

[JoeyPro]

What RPM do you other 3.8 try to keep it in. When your just cruising around tryin to save gas?

I shift at 3k and it stays around 2k when I drive does that sound about right?

Also I have always wondered, when I am doing like 30 or so, is it better to be in 4th gear and pull around 1.5k or be in 3rd and be a little over 2k or maybe even 2nd an run a little over 3k

[Turbo V6 Camaro]

shift at 2500 and try to keep it at about 1400-1800 that were i get my best milage

[ August 24, 2005, 09:02 PM: Message edited by: viper04af ]

[matt3989]

srry for the newb question but what is the pcv valve and wat does it do?

[PalmHarborBlkv6]

how difficult is it to replace the O2 sensors? I have 2000 with
70K mileage. My mileage is poor too.

[grayman]

Originally posted by PalmHarborBlkv6:
how difficult is it to replace the O2 sensors? I have 2000 with
70K mileage. My mileage is poor too.

not hard. you can use an open end wrench if you have the clearance or a special socket. you will find the special socket in the specialty tools section of store. it is a deep socket with a slit in it to slip over the wire harnes. you may need to use some penetrating oil. clean up the manifold and wire harnes of penetrating oil before you install the new sensors.

disconect battery before you start.

you can get stock o2 sensors from gmpartsdirect.com for a real good price. search the catalogue for 2000 - v6

[Turbo V6 Camaro]

i just got 14.5 MPG with all city driving and checking to make sure my wasgate worked like it was suppose too !!!!!! (aka the turbo was spooled.......alot lol)

[Yaba3800]

i get 18 m.p.g. on my 3.8 ive done everything i can (cept the pcv) to improve it. nothing will

[Turbo V6 Camaro]

Alinment and tire PSI are huge factors too!!

[Little G]

weight is a huge factor, I get 25mpg.

[DanT]

I get around 280-300 miles on a tank of gas right now, and my motor is running a custom cam and headwork. It's ever so slightly less than before the mods.

[rhouse21]

I might be tipping my hand as the king of the geeks, but I've been tracking my fuel mileage for all of my car's 201+K miles in an Excel spread sheet. I've posted some of my charts at the links below.

http://home.comcast.net/~rhouse21/Ka..._Mileage_1.jpg
http://home.comcast.net/~rhouse21/Ka..._histogram.jpg

If you look at the mileage histogram chart, you can see three humps for the different types of driving I do. From the chart I've averaged roughly:
14-16 MPG for pure city driving,
20-23 MPG for mixed city/highway driving, and
26-31 MPH for straight Highway driving.

I've had a pretty unique experience with this car since it's done a fair amount of time living in Michigan, Boston, DC, CA High-Desert, and back to DC. In my experience, Joey's mileage is a little low but not that much out of line of what you'd expect from pure city driving. (When I was in Boston, it wasn't unusual to get a 12 or 13 mpg tank.)

I might theorize that the synthetic lube, K&N filter, platinum plugs, or Bosch O2 filter might give me a few extra percent here or there, but the single biggest impact to my mileage that I've measured over 700 or so tank-fulls is how much I put my foot in it. Higher speeds and frequent gear changes KILL your mileage. Period.

There are a lot of magic-bullets out there that claim to miraculously improve your mileage. I've tried a few, but they mostly didn't pan out in the data. Until one of you guys find the magic bolt-on that gives you 400 rwhp and 50 mpg, my best advice for good mileage is to flow with traffic, keep your revs low, and use cruise control if you have it. Yeah, driving like a grandma might not be that much fun, but I guarantee that your mileage will go up.

[ August 29, 2005, 06:56 PM: Message edited by: rhouse21 ]

[PalmHarborBlkv6]

If you run the AC south florida camaro......it eats power and thus
gas. I live in Tampa and when I use AC in summer it costs
me gas mileage.

[JoeyPro]

Little G what type of weight reduction have you done? Or a better question, what can I do that wont cost me much.

rhouse, thanks that is the kind of info I was lookin for. Yes I do pure city driving, so I guess I shouldn't worry so much.