well, just returned from a 1,000 km trip (come n go)... after my calculations my car averaged 12.7 km/l (about 30 mpg) which i consider normal for a 2.4... the problem is, since i bought the car (used auto 2001 sunfire), it has never given me more than 6km/l in the city (14 mpg) i consider this extremely low, and considering that the car has been properly tuned up and that it gives me nice numbers on highway i guess something's gotta be wrong.. i know the mileage decreases considerably in the city but come on.. there's no v8 under my hood.. and i'm not that much of a leaded-foot either... might be the fpr? any kind of leak? i would really apreciate your help!
thanks,
Could be a number of issues:
IAT could be reading wrong air temps thus running a little bit lean/rich
TPS could be giving false reads to the ECU
FPR not able to govern the right amount of air to fuel (my guess too)
o2 could be telling your car to run more fuel than air, thinking your running lean
Injector stuck open (but youd smell a slight hint of gas)
Spark plugs gapped wrong or wrong plugs to begin with
Coil going out, not giving ampel spark
ECU going bad (knocking on wood)
etc etc etc
It sucks but unless someone else can think of something different... Start moving down the list!
Go with your gut first
now DIE!
first of all, thanks for your reply...
now, i've driven this car for almost five years and its mileage in city has always sucked (only in the city), now, in this time i've taken the car to different mechanics, they have changed the o2 sensors a dozen times, cleaned the injectors (though i do get a strong gasoline smell sometimes but ive got no cat), changed the sparkplugs, IAT, filters, etc etc, charging me hundreds of dollars until now and the problem has not been solved a bit... there was a time i simply accepted the mileage, but seeing recently that the car CAN actually give me good mileage in highway, i wonder why not in the city (where most of my driving is -.-)
I'll try to check the other issues you listed, meanwhile i'll see if someone comes up with another solution or same experience.
later,
I get about 13 to 16 MPG consistently. This doesn't surprise me, given my short tripping and low amounts of highway travel. My car hardly ever gets a chance to warm up properly, and makes a number of stops and starts. I'm also a bit lead-footed. This is with the "economical" 2.2 OHV engine, which should have an advantage in mileage over your car.
Given my own experiences, I'm not convinced you have a problem. If you aren't seeing any other "symptoms", then I'd consider it perfectly normal. You said yourself that highway mileage is fine -- so clearly something about the city driving is making the difference. Also, I find "official" highway / city mileage ratings are typically out to lunch. The city ratings are far too optimistic.
Shop Manuals, Brochures:
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I have the 2.2/4 speed automatic and have NEVER gotten below 24 mpg. That 24 was an entire tank of nothing but city driving (mostly short trips) including a lot of idling with the A/C on.
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2000 Cavalier Coupe, 138k miles, 2.2 Auto, Silver (alive)
1999 Cavalier Sedan, 237k miles, 2.2 Auto, White (dead)
i don't want to simply resignate to a 14 mpg... it just seems too low for me! there must be something missing in the puzzle.. but thanks anyway for the replies guys
Just to clarify on what I do to deserve such poor milage, my typical weekday involves:
- 4 mile commute to work
- 1 mile to a fast-food location without a drive-through or seating (so car is parked and shut off)
- 1 mile to one of the places I eat lunch
- 2 miles back to work
- 4 miles home
So, I end up restarting the car up about 4 or 5 times a day, barring any additional errands. In winter, I barely ever see the car reach operating temp. On the other hand, this short-tripping routine still means I get about 2-1/2 to 3 weeks on a tank of gas.
Shop Manuals, Brochures:
www.kenmcgeeautobooks.com
Get a new air filter.
Get the fuel injection flush done (injectors may be sticking)
See if the sensors are functioning correctly, especially the o2 sensor.
Our cars have relatively high fuel consumption at idle. That means any time sitting still is going to pound your MPG numbers into the ground. If you can do 30mpg highway with a 2.4, there's nothing wrong with your car. You're going to have to change your driving habits.
Pay attention to your foot. Use the gas as if you have no brakes. Use just enough acceleration to go where you need and maximize coasting. Keep your eyes on the light ahead and don't tailgate. The second a light turns red, your foot should be off the gas (given the car has enough momentum to make it to the light). If you find your right foot going directly from the gas to the brake and vice-versa, you're not doing as well as you could be. In the city, (unless you're stopped at a light with an auto), you should drive so that you spend as little time as possible with your foot on either pedal. Also, coast in D, not N.
2002 Cavalier 2200 5spd
seems fine 30 mpg on highway is normal...i get bad city driving too but on the hight its crazy how much better it is...Change you driving habits and you'll see a difference
