Went to the dealer and....

[goldfinger]

talked to Mr. Goodwrench.

The reason I went is because I've been getting horrible gas mileage (14mpg) and I couldn't pinpoint why. Keep in mind that this is a 2.4L DOHC 4 cyl.

Checked plugs, o2 sensor, cat, dragging brake, ect. I had 2 seperate vacuum leaks in the past 2 months which I had found and fixed. I finally went to the dealer and talked to a tech who was actually willing to spend a little time talking.

He asked me how long it had been since I disconnected the battery........ I told him about 75 miles ago to reset the SES light.

He showed me in their book where it can take 50-150 miles for the computer to re-program the "Adaptive Fuel Delivery Memory", 25-50 miles for the "Fuel Rate Consumption Memory" and several minutes @ 1500-2000RPM to re-calculate the idle speed setting.

He said to go through another tank and if the next one is still bad to come back.

Didn't cost me anything, but has anyone ever heard of this? It makes sense........ just wondering if it's true, or dealer BS.

 

[DJStillman]

Most modern cars have computers with requirements for relearning their specs and their present situation, but I have never heard the requirements in so many miles. Usually, after reconnecting the battery, take a 15-30 minute drive on the highway driving as you usually would, and that should have it all fixed.

Personally, if after one whole tank of gas you still have the problem, then I would be highly suspect of a problem somewhere else than the computer's relearning.

 

[digitaldrifter91]

its hard to say how long the computer takes to learn driving styles. the ecu controls the air flow mixtures etc.

my car takes about 10 minutes driving to re-learn my transmission habbits...and a day for the fuel to fix up. usualy this helps....i run the car normal for a day or 2 and then i will be set with better gas milage.

usually i do this every season tahnks to gas mixtures.

usually before i do a fuel system cleaner then after the tank i reset my ecu.

 

[Christopher R. Wise]

Why did you reset the SES light??

What was the code???

CRW

 

[goldfinger]

I don't know what the code was for the SES light, but the problem was pretty obvious.

It came on, had irratic idle, ect. I looked under the hood, tracked the noise and I could see the intake duct wasn't sealed properly. I could even feel it sucking air.

I fixed it, reset the light and it hasn't came back on yet so i'm about 99.9% sure that was the problem.

Nobody drives it but me, and I only drive it 30-50 miles a week which is 100% city driving and witht he A/C on. Even considering that...... 14MPG just doesn't seem right to me with a 4cyl. New it showed 22/32MPG on the sticker so I'd at least expect 18 or so.

Who knows.... maybe I'm expecting too much. It doesn't kill my wallet too bad since I don't have all that far to drive.

 

[guitargeek]

I should think 14 is way too low for that car... **** , my engine has almost twice the displacement, and I can still break 20 in city driving (3800 V6).

The 2.2 is known for eating fuel injectors... maybe something is up with one (or more) of them?

 

[JTK]

That is odd. A co-worker of mine has a 2002 saturn VUE with the 2.2L GM ecotec. It's AWD, with the CVT auto transmission. The best he gets with mixed driving is 14mpg. The thing runs like a top & the saturn dealer can't find anything wrong. They did say they are getting many complaints about fuel economy with this model. I can drive my 3.2L 205hp isuzu rodeo all day long in 4x4 and get higher MPG!!
G/luck
Joel

 

[Mike_dup1]

Does anyone else besides you drive this car?

If so, there in may be the poor mpg problem.

 

[goldfinger]

I hate to bump up this post but I thought I would let everyone know that somehow or another the gas mileage has improved greatly.

I'm back up to 19-22MPG depending on how I drive, which is right where I expected it to be.

I did add some MMO and injector cleaner, but there's no way that could attribute to such a large jump.

Looks like the dealer gets credit for the fix.

 

[gundam2000]

Your mechanic was correct. There are several fuel trims which take time to set. the long term trim can take quite a while depending on the vehicle. Varying your driving to show the computer your true driving style will help it reach correct values sooner. If you do alot of city driving do not reset the computer then go for a long highway cruise, your city mpg will suffer greatly.