Gas mileage seemed to recently decrease from 280 miles (full tank)to about 210 miles. What can be the problem?

Asked by Feb 13, 2008 at 06:03 PM about the 2001 Mitsubishi Galant ES V6

Question type: Maintenance & Repair

I do oil changes every 3000, change air filter every 12000, and had a full tune up at 68000 miles. I now have 75000 miles on it.

8 Answers

it is not unusual to lose some millage with age of cars ,also todays gas is junk,if running reg,run mid grade with a bottle of good fuel injector cleaner-lucus is great.

1 of 1 people found this helpful.
45,275

How has the weather been? I notice a decrease in gas mileage here in PA in the winter on the colder days. Basically, gas is not always the same density -- when it is hot out, gas is less dense, when it is cold, gas is denser. So when it is cold the same volume of gas that is fed to the fuel injectors is not the same volume as in the summer months.

285

Bad gas, dirty injectors, dirty air filter, spark plugs, timing, air to fuel ratio etc.

2 of 2 people found this helpful.
585

Timing? The ECU in these cars controls the timing. No matter what you do to try and adjust it, the ECU will just correct it to the proper adjustment. and A/F Ratio? Are you kidding me? This is something you cannot touch on these cars without any type of standalone tuner. All of this is preprogrammed into the ECU, and I highly doubt he is adjusting these settings from a tuner. And to the person above talking about going from regular unleaded to mid-grade unleaded, don't be so clueless. The 6G72 in his V6 Galant requires Premium Unleaded. True he might not be using the required Premium, but for the extra $1-$2 it costs per tank, it would be completely stupid not to use the correct fuel. Sorry. /rant, but I hate when people give B.S. info that in no way will help the OP figure out what he is posting for.

8,675

When did this start exactly? If it was shortly after the 'full tune up', it could be plugs were not gapped properly... It could be one of the many sensors that corrects the A/F ratio is dirty and throwing the mixture off... It could be a dirty fuel filter... It could be dirty injectors... It could be dirty valves... It could be that the gas station you get gas at has newer pumps that now are out-stopping sooner and you have slightly less gas in the tank... It could be the valve cover gasket is leaking into the plug wells and acting as a dielectric reducing spark propagation... It could be several other things... There is a decent list of what the problem could be... So where to start is your next question, right? 1) Pay attention to MPG in the future not miles per tank because how close to full you get depends on the gas station. 2) Injector/Intake cleaner... Not just the little bottle that goes in your tank but the two stage that includes running a cleanser through your vacuum lines to the intake manifold... Seafoam is the DIY'rs brand here. 3) Fuel Filter (If it's serviceable on your car... Some aren't... some are really hard to service(Inside the gas tank, but still supposed to be replaced)) 4) If your still having problems, pull your plug wires off the plugs and make sure there is no oil around the bottom... (Would mean a leaking valve cover gasket... a simple problem, but an annoying and often overlooked one)... While you're there pull at least one plug and make sure they were gapped correctly and that they aren't fouled up... If you're STILL having problems or have any questions post back...

1 of 1 people found this helpful.
75

The use an fuel injector cleaner on a regular basis is one answer to your problem. Another is if the car has been only in city driving is would be best to get a long highway at a steady speed at 70 -75 mph for about 1 hour one way. This will allow to blow out carbon buildup on your engine. Making it more efficient.

1 of 1 people found this helpful.
6,265

a little late to the party aren't ya there crawfish ? lol

1 of 1 people found this helpful.
155

Post to post. R u a mail man Ora male bug...lol

Your Answer

Galant

Looking for a Used Galant in your area?

CarGurus has 1,045 nationwide Galant listings starting at $2,450.

ZIP:

Mitsubishi Galant Experts

  • #1
    Tom Demyan
    Reputation
    780
  • #2
    dandyoun
    Reputation
    770
  • #3
    Daniel Foster
    Reputation
    580
View All

Related Models For Sale

Used Mitsubishi Lancer
53 Great Deals out of 5,682 listings starting at $1,699
Used Honda Accord
1,084 Great Deals out of 65,604 listings starting at $561
Used Honda Civic
682 Great Deals out of 63,747 listings starting at $999
Used Nissan Altima
1,069 Great Deals out of 78,518 listings starting at $1,500
Used Toyota Camry
936 Great Deals out of 89,704 listings starting at $300
Used Nissan Maxima
304 Great Deals out of 22,137 listings starting at $1,200
Used Mitsubishi Lancer Evolution
10 Great Deals out of 578 listings starting at $13,980
Used Mitsubishi Eclipse
31 Great Deals out of 1,178 listings starting at $1,999
Used Toyota Corolla
868 Great Deals out of 59,726 listings starting at $850
Used Mitsubishi Mirage
21 Great Deals out of 4,006 listings starting at $3,995
Used Chevrolet Impala
531 Great Deals out of 34,814 listings starting at $990
Used Hyundai Sonata
783 Great Deals out of 54,589 listings starting at $1,500

Used Cars For Sale

2012 Mitsubishi Galant For Sale
5 Great Deals out of 224 listings starting at $4,000
2011 Mitsubishi Galant For Sale
153 listings starting at $5,000
2010 Mitsubishi Galant For Sale
84 listings starting at $3,990
2009 Mitsubishi Galant For Sale
131 listings starting at $3,995
2008 Mitsubishi Galant For Sale
49 listings starting at $2,995

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.