What's up with the low mpg ?

TdotAlero · 05-21-2009, 11:53 PM

I have a 4 door 3.4 and it's becoming more and more of a gazzler. I got half a tank two days ago, drove around the city, did 130 kms (checked with trip meter) and now I have an empty tank. Wtf why is my Alero burning so much gas ? I don't really know much of cars performance wise, I am learning from books and practise but I honestly don't know how to improve my mpg...
I don't use AC I don't floor the gas I drive like a casual driver.. oil change some 2000kms ago, spark plugs will be replaced soon. What else should I do to spend less on gas ?

Nate's Alero · 05-21-2009, 11:56 PM

sounds strange, no lights or codes?

TdotAlero · 05-22-2009, 12:00 AM

Quote:

Originally Posted by Nate's Alero

sounds strange, no lights or codes?

I have the service engine light on, but if I recall correctly it has something to do with the gas tank cap. WHat's more strange it burned less in winter than now. I really don't mind spending a few more bucks on gas, it's a V6 after all, but wify has been complaining.. and it's painful watching the gas needle drop. Just though it's something preventable, maybe new filters ?

cherrington17 · 05-22-2009, 12:01 AM

injectors dumping too much? fuel filter broke? fuel pump broke?

get it scanned, first.

i have the 3.4... i get at least 25mpg. usually 27ish.

Redog · 05-22-2009, 12:14 AM

^^ Yeah, fuel filter? Air filter? Plugs and wires (tune up)?

Doesn't sound right, get these things checked first.

Are you sure that the gas cap is bringing on the SES light (P0442 code) Could be something else that causes MPG drop like an O2 sensor

Valley olds · 05-22-2009, 12:17 AM

Posted the same thing as reddog. Anyways, yeah, first just try the tuneup, and see if that helps any.

CactusWill · 05-22-2009, 03:15 AM

A plugged up fuel filter would restrict the flow of gas, not increase it, I don't know why you guys are saying its the fuel filter.

What you need to do is get an accurate read on what mileage you are actually getting. Fill the tank, record the mileage, fill the tank again, and calculate the mpg. You've got 2 people driving the car, and just saying "130km per half tank" is not a measurement of miles per gallon.

WhiteV6 · 05-22-2009, 04:12 AM

How old is your O2 sensor? Before you change your spark plugs, do this.
http://60degreev6.com/forum/f86/usin...cleaner-t35230

Plugs, wires, O2 sensor, fuel filter, air filter. If none of those have been changed for a while, it is probably time.

A cloggged cat will also cause poor mpg but you should notice less power if the cat is going bad.

smokey · 05-22-2009, 04:31 AM

I'm in the same situation. I usually get around 15mpg most highway driving. I scanned mine and there was no error codes. I also changed the air filter, but I think mine is going crazy because of the LIMG leak that I have, however that should be fixed in few days and i will see if it has improved. The best mileage i got was 23 MPG. I was going nuts when gas $1.30 a litre, now its $97 man eff gas companies.

cherrington17 · 05-22-2009, 07:22 AM

Quote:

Originally Posted by CactusWill

A plugged up fuel filter would restrict the flow of gas, not increase it, I don't know why you guys are saying its the fuel filter.

What you need to do is get an accurate read on what mileage you are actually getting. Fill the tank, record the mileage, fill the tank again, and calculate the mpg. You've got 2 people driving the car, and just saying "130km per half tank" is not a measurement of miles per gallon.

thats why i was wondering if the fuel filter broke... maybe letting too much pass though. unlikely.. but hey... weirder things have happened.

Nate's Alero · 05-22-2009, 08:27 AM

i would say, plugs, wires, air filter, fuel filter, 02 Sensor (upstream only) EGR plugged uP?

TdotAlero · 05-23-2009, 09:39 AM

Thanks guys, I didn't want to take my ho to the local rip-me-off shop to get it checked out. Im gonna pick up new spark plugs today, maybe wires and filters. I have to see how much I can change alone (with my father in law's help). And the cleaner too. If the mpg (km/l for us on this side of the border) doesn't change then I need to take it to a shop.

smokey · 05-25-2009, 08:15 PM

ok i replaced the stupid spark plugs and fixed the stupid LIMG leak. I noticed that my car is running much colder, the temp guage never reaches half in city traffic, and i noticed some good MPG improvement, so it might be your plugs, they costed me about a $100

zzyzzx · 05-25-2009, 08:26 PM

Quote:

Originally Posted by CactusWill

What you need to do is get an accurate read on what mileage you are actually getting. Fill the tank, record the mileage, fill the tank again, and calculate the mpg. You've got 2 people driving the car, and just saying "130km per half tank" is not a measurement of miles per gallon.

I agree that you do need to make measurements based upon a whole tank of gas. I have been getting 26-28MPG in Baltmiore-Washington DC traffic with my 1999 V6 with an ATX, but I also drive with gas mileage in mind.

I'm also curious as to how many miles on the car before the LIMG problem.

I'm also curious as to how many miles you can drive after the dash light goes on.

crackakam · 06-06-2009, 04:05 PM

what is a limg problem my alero get hot and cold anyone know that that is from i rebuilt my motor and then it started doin the geting hot and cold thing

acat550 · 08-03-2009, 08:22 PM

I just went on a trip to Estevan and averaged out 36 mpg doing 110kmh. I thought that was pretty damn good, but i do have the 2.4 however. 130 per tank however something is desperately wrong, get it checked!

Raziel · 08-04-2009, 12:10 PM

odd, I have the 3400 and when I fill up my tank, I can go to weyburn and back and then drive to work and back and around when I need and get about 450-500 kms out of a tank, and sometimes im not nice to the pedal either(serious road rage, but at fault from stupid drivers). So yah go over the car with a fine tooth comb, maybe you have a leak in the fuel system somewhere, check all the lines and along the gas tank, if not try what everyone else has been sayin and go from there.

Raz

worknprog.99 · 08-04-2009, 12:25 PM

maybe you get good gas mileage its just your gauge reads incorrectly like mine does.. it will say im on gas light righ after i put in half a tank or more lol