2000 elantra crappy gas millage

[kimmy79]

Ok my car all of a sudden started getting crappy gas millage. I went from getting about 450 miles every time i filled it up to not even getting 200!!!! I have all the maintence done on it like I am suppose to, I am not driving any differently than usual and there are no check engine lights on. On my last oil change i told them about this problem so they put in a new pcv valve and a fuel system cleaner and still nothing. I bought this stupid car because of the warranty and the good gas millage they were suppose to get but I dont know what else to do. I have taken it to Hyundai they cant find anything wrong with it, tried different octane gas's and still nothing. Can someone please help with this.

[Tiburon99]

well, after my mom got her 99 Sonata GLS V6 tuned about two years ago the same thing happened. She started loosing a lot of gas milage. People at the company said it is because they do a "boost" as in power or such to the engine when you get tuned up. That might be the problem in your car to!

[tibby01]

does the performance feel like its gone down at all?

[kimmy79]

Nope the performance hasn't gone down at all. I mean other than the gas issue it drives the same as it did the day I bought it. I just dont know what else to do and it really is a good car and it is paid for I dont want to trade it in but I just cant afford to put gas in it every other day. I mean my brother has a SUV that gets better gas millage and it is a V8!!!

[cinsom]

Yes, myr friends car was the same way, 2002 Elantra. She's really upset about the crappy gas mileage now.

[nippjas]

Listen to it carefully...How does it idle? I bring this up because I recently had a coilpack replaced. My idle sounded OK, but if you really listened it kinda hesitated here and there. I had complained to the dealer that my economy went from 35.6 mpg to 23.3mpg, yes I track every mile, every tank...well the jist of this story is...This is my daily driver and I too bought it for fuel economy. It wasn't until the coilpack completely failed for the ECU to record an error code. After this was replaced my idle purred very smoothly and my economy went back to around 34-35mpg hwy.

This may or may not help....just something to look at.

Jason

[cinsom]

it hesitates big time! It's been in the shop several times for this. They've replaced transmission modules, softeware upgrades, but ti still idles like this. The gas mileage declined when this idling occurred.

[nippjas]

Originally Posted by cinsom

it hesitates big time! It's been in the shop several times for this. They've replaced transmission modules, softeware upgrades, but ti still idles like this. The gas mileage declined when this idling occurred.

In this case my comment is very valid. Before you take it in or try to replace part check the ground cable from the coilpack to the car, clean it up with a wirebrush and reassemble using dielectric grease.

If idle continues I would focus on sparkplugs, coilpack, or injectors.

Jason

[cinsom]

coilpack?

[nippjas]

Originally Posted by cinsom

coilpack?

Yes the coilpack. Electronic ignition system. the 2 liter elantra does not have a convential old-school distributor cap. It has 2 electronic ingnition coils. Follow you sparkplug wires...one end going to the spark plug which fires into the cumbustion chamber. The other end is attached to the coilpack.

Jason

[cinsom]

ok, thanks

[andrew348]

my 2 cents

Recently i have seen a rash of canister purge valves go bad on these vechicles . what the purge valve does it allows the vechicle to vent unburned fuel from the carbon canister . when they stick open you wind up sucking fuel into the intake . you gey a bad off idle hesitation and poor fuel economy with no check engine light . rember i am saying this with out looking at the car . best of luck let me know how you fair out .

[DJT]

I drive 170 miles per day. My Accent has over 140,000 miles and I need to start looking for a new car. I want a car that will give me the highest milage, be relible with good running history and not very expensive.