Last post on Apr 21, 2011 at 10:06 PM
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Chevrolet Impala, Fuel Efficiency (MPG), Sedan
Apr 24, 2008 (2:26 pm)
Does anyone know a practical / economical way to change out the 3.29:1 axle ratio on the LTZ (3.9L engine) for the 2.86 ratio from the 3.5L engine?
#85 of 123 Re: 2006 Impala SS [quietpro]
Apr 24, 2008 (6:34 pm)
I'm getting 32 mpg hwy with my 2004 Impala, but it has the 3.4L engine.
#86 of 123 2002 3.4 gas mileage
May 06, 2008 (4:43 pm)
My 3.4L 2002 impala has about 110,000 miles.
I just got 33.5 mph on the "highway." That included driving through a few small towns with stop and go traffic.
Most of it was 55 - 65 mph.
City driving is about 25 - 27
I try to "hyperdrive" by anticipating stop lights and stop signs. No jack rabbit starts.
Lots of coasting when possible.
#87 of 123 Re: 2002 3.4 gas mileage [superdow]
Jun 16, 2008 (8:21 am)
I have a 02 impala with 3.4 and was getting about 31 MPG on highway and around 28 in city. It seems suddently I lost about 10 MPG and I have tried everything I know and even had it diagnosed at a Best of the Best Shop. They told me the ejectors were dirty and needed cleaning, got it done there. No change. The Spark Plugs have been replaced with original kind, Fuel Filter replaced, Air Filter changed, MAP Sensor Cleaned, Fuel Valve checked, and problem has not been resolved.
#88 of 123 Re: 2002 3.4 gas mileage [bena8837]
Jun 16, 2008 (9:23 am)
How many miles do you have on it? Could it be your catalytic converter is getting clogged? If you feel like you're losing power as well, that might be the culprit (I never had a problem with mine, but I know others here has posted stories about the converter clogging up and causing power/economy problems.
#89 of 123 Re: 2002 3.4 gas mileage [nosirrahg]
Jul 31, 2008 (6:59 am)
I started writing about a 10 mile loss in mpg several months ago. I tried everything I knew could be the problem by replacing the spark plugs(which appear to be fine), Air Filter, Fuel Filter, Cleaning the MAFF ? Filter on the air intake with spray, and finally had it taken to a (Best of the Best) Shop and had it (analyzed). They told me the ejectors needed cleaning and I said Ok. Drove it home and no change. Since then, when I have time I go under the hood and look at possibilities. About 3 weeks ago I notice moisture aroung the Coolant Temperature Sensor. So I decided to replace it. I drove to Dallas about a week later and guess what, I regained my MPG, 31+. Also, on the way there (about 400 miles away) I started having problems with the catalytic Converter and had it replace when I got there. It was still in warranty since my car only has 60K. My car always appeared to run in a temperature of about 191 degrees, which I believe I had read was within range. Heads Up to everyone who owns car with 3.4. Thanks for your help, appreciate it!
#90 of 123 2008 LT 50th Edition
Aug 26, 2008 (4:38 pm)
Just bought this Impala and first 750 miles with computer average is 22.7 in mixed highway and city driving with plenty of short run ins. This Impala is 3.5 L with 18" wheels and sports tuned suspension. I guess it will increase as this is break in period. Noticed big difference with 18" wheels and tight suspension as it stick to the roads. I wondered if this affects fuel consumption as well.
#91 of 123 Re: 2008 LT 50th Edition [saxe10595]
Aug 26, 2008 (6:33 pm)
Sticky tires will likely decrease your mileage; also if the diameter of your new wheels & tires is bigger than the factory setup, your speedometer/odometer may be off somewhat and give you a false (lower) reading.
#92 of 123 Re: 2008 LT 50th Edition [nosirrahg]
Aug 27, 2008 (7:06 am)
this is factory installed. Came with 50th anniversary Impala and I guess the speedometer is adjusted from the factory as this was standard on the vehicle. Will post as I drive more about the mileage and alco check between fillups to ensure that computer mileage ie similar.
#93 of 123 Re: 2008 LT 50th Edition [saxe10595]
Aug 27, 2008 (6:10 pm)
saxe--Glad to hear a report from an owner of a 50th Edition. I own a 2006 LT2, and considered trading for a 50th Edition--primarily for the Jewel Tint red and the sport suspension; I've already added the SS-style spoiler and the wheels/tires are an optional piece at any time. Keep us posted on handling and mileage as you get more miles on it. Clark