Mpg Woes...

[jiffy]

Ever since I bought my Alero about a month ago, I have gotten TERRIBLE mileage. EPA estimates are 29 highway 22 city, but I know you will probably never get the actual estimates. 75% of my driving is highway, and I have gotten anywhere from 17-20mpg since day 1. I don't drive hard either, infact, I have never driven this gently.

I took it to a dealer today, their printout said "Test sytem, no codes no problem found" So, no luck with anything there. I do have another appointment next week at another dealer (this first place got me in sooner), that I may keep and have them double check this.

While in, I also had them check my horn, because it wasn't working right, so they replaced that. They also replaced the front right wheel bearing and hub assembly because it was "noisy and loose"

Anyways, back on topic...I still think my mileage is just unacceptable. 17mpg would be reasonable for city driving, not 75% highway. My friend has a 2000 Chevy ext cab 1500 with the 5.3L V8, and gets very similar milage to my 3.4L V6


New fuel filter? Fuel Injector Cleaning? I don't know what to do...

[Vtolds]

17 mpg isnt to uncommon with the 3.4, hell I never broke 22 mpg in my 2.4.

[-Alero-]

change the fuel filter, fuel system cleaner always helps, try using engine internal cleaners such as seafoam or deep creep. also running synthetic oil always helps out, and having an after market intake helps as well. i get over 300 miles per tank quite often.i just take good care of the engine treatment i guess.

[AftermathAlero]

make sure your tires are aired to 32-35 psi cold.

[jiffy]

Ok, here is some strange stuff...

I just got back from a 150+ mile "trip" and did 99% thruway, cruise set mostly at 71mph, or 61mph some of the time. My mpg...26.5!

This is something I see as highly acceptable. If EPA estimates are 29, and I can get 26 going a little faster I am very happy.

1. I wonder if something the dealer did had an affect on this.

2. I have notice that my rpm's seem jumpy when I doing city driving. What would seem like an equal movement of the pedal yeilds noticably different rmp movements. Possibly something there isn't right, causing me to use much more gas in the city, and therfore reducing my highway/city mix.

I actually did a little calculation, to figure out what my mpg should be driving 70% highway and 30% city, using 26.5mpg as my highway average and an estimated 20mpg city (EPA says 22). Based on this calcuation, I should be getting ~24.2 mpg. Last time I checked it was under 20, closer to 18.

I will need to check some regular driving over the next few days to see if anything changed there.

[AftermathAlero]

yeah.. my mpg when at 60mph i get 32 mpg, then at 75 mph i get 25/26, when at 70mph.. i get 28 mpg.

thats with my 20's on the car too and 18's.. I didn't see no change in mpg. I also change fuel filter every 10k, and injector cleaning at 30k miles.

City driving i get 20mpg.

[jiffy]

Originally posted by AftermathAlero@Mar 13 2005, 03:10 AM
yeah.. my mpg when at 60mph i get 32 mpg, then at 75 mph i get 25/26, when at 70mph.. i get 28 mpg.

thats with my 20's on the car too and 18's.. I didn't see no change in mpg. I also change fuel filter every 10k, and injector cleaning at 30k miles.

City driving i get 20mpg.
Do you have any mods like a WAI/CAI? 32 is high for the 3.4L, especially with 20's.

[AftermathAlero]

borla exhaust, msd igntion coils, msd wires, ac delco rapidfire spark plugs, and a WAI. I keep my front tires at 40 psi and rear at 35psi (cold readings.)

[alero440]

I get around 17 and I do mostly city... I have replaced my spark plugs, fuel filter, EGR, and I drive somewhat nicely and nothing helped, not even replacing the bad EGR. It's a joy owning a V6 isn't it? I didn't get that great of mileage with my 2.4 Alero either.

[doubleN0alero]

on a good day, highway or city, i get 22...and thats if its a blue moon on the third tuesday of the month on a leap year

[eag182]

Originally posted by AftermathAlero@Mar 13 2005, 04:24 PM
borla exhaust, msd igntion coils, msd wires, ac delco rapidfire spark plugs, and a WAI. I keep my front tires at 40 psi and rear at 35psi (cold readings.)
Why do you keep a higher pressure than what olds recommends?

[AftermathAlero]

Originally posted by eag182+Mar 16 2005, 10:28 PM--></div><table border='0' align='center' width='95%' cellpadding='3' cellspacing='1'><tr><td>QUOTE (eag182 @ Mar 16 2005, 10:28 PM)</td></tr><tr><td id='QUOTE'> <!--QuoteBegin-AftermathAlero@Mar 13 2005, 04:24 PM
borla exhaust, msd igntion coils, msd wires, ac delco rapidfire spark plugs, and a WAI. I keep my front tires at 40 psi and rear at 35psi (cold readings.)
Why do you keep a higher pressure than what olds recommends? [/b][/quote]
it all depends on the tires. on my nitto's max psi is 51psi.

The factory recommends 30psi cold for the goodyear LS.. which is way too low to begin with. Most tire shops say the right pressure is 35psi cold. They want 30 psi cold is for ya to wear out the tire quicker because the less air you have the more traction the tire is contacting the surface.

[eag182]

Aye. I shall be making a trip to 7-11 tomorrow.

[Redog]

On road trips I can get 32 MPG but once and only once I did get 37 MPG, I still do not know how.

I get about 18 to 21 in the city

[1WhiteOSV]

Originally posted by Redog@Mar 17 2005, 03:45 AM
On road trips I can get 32 MPG but once and only once I did get 37 MPG, I still do not know how.

WOW! :eek: That's nuts Redog...you have the 3400 too don't you? I took a roadtrip last week and drove about 90mph most of the way there and back and got 21mpg (all highway). In the city I get 17 on average. I do have 57,000 miles on my Alero and havn't changed the fuel filter at all ever so I should probably do that. I also know that changing tranny fluid to fully synthetic helps gas milage a lot, I did it in my S-10 that I used to have and my gas milage went up like 5-6 mpg.

[tenny]

highest that i've gotten is 31mpg

[tenny]

P.S

since i've gotten my car I have kept a spreadsheet and my avg mpg over the past 20,000km is 26.9 MPG.

3.4L engine and the auto obviously

[turtles_ride]

i remember drivin the 'ho down to Florida a couple years ago, all highway driving obviously, and i kept getting better mileage as i went further south (i went in April). I kept trackof how far i went, and how much gas i put in and at what prices. I started my trip getting around 400km per tank with mixed city and highway driving, prolly around 500km/tank if i was just on the highway. Every time i filled up and ran thru a whole tank of gas my mileage got better and better. On the way home i thunk i got as much as 700 km/tank, i couldn't believe it. I quess there is some truth to the wise tail that your engine needs a good run to clean it out every once in a while. I think the 8 1/2 hour drive to oldsmans would clean out my engine pretty good again. Think i should put that seafoam in or something for the long trip?

[tenny]

I never put any additives in my car, though i've heard that seafoam is the only one worth putting in an engine.

I had a how to for it for my camaro and to do it all properly it looked like a fairly long process and big job