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Hello all.

 

I took my car into the dealer today to have them troubleshoot a hesitation problem. Of course, the car is running beautifully now so there is no problem to solve!

 

They said there was no codes stored in the memory. I did have the check engine light flash several times when it was sputtering until it warmed up, then the light went away. Twice when it happened I counted 11 flashes, but then the car started running better and the CEL went out. Should that have stored a code?

 

They greased the contacts between the ignition coils and wires. I'm hoping this is the problem, but I kinda wish they found something.

 

They said the air/fuel sensor is reading slightly lean. Where is the air/fuel sensor and what is the side-effect of a lean AF mixture?

 

They said the PCV valve was like new and didn't jump at the suggestion of replacing the fuel filter saying that I'd be better off waiting until the problem could be reproduced. That shocked me! I thought they would jump at any chance to do more and charge me more money! They must have ran out of time!

 

Anyway, just trying to learn about the AF sensor, and wondering if anyone has suggestions on how to reproduce or pinpoint this hesitation:

 

Usually cold wet morning

car starts fine, idles fine

pull out of driveway and pull away normally

car sputters and bogs down almost to the point of stalling

After about 15 or 30 seconds, the car starts to run better.

After a minute or two, everything is fine again.

CEL flashed during this episode on 3 or 4 occaisions

Was happening about twice a week for a while (and I don't drive to work everyday, only when I need to travel somewhere for work), but now does not seem to be happening as much

2003 5 spd Outback Sport, 110k kms

new spark plugs and air filter

not sure what else might be relevant .... uh ... it's silver!

 

Thanks,

Chicobiker

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mileage?

 

a/f sensor is the o2 sensor

 

nipper

 

 

110k kms or approx 60k miles.

 

So this sensor senses the amount of oxygen in the air being delivered to the spark area? Can the air actually be controlled or only the fuel? Does "lean" mean: not enough oxygen? Would that mean that the fuel doesn't burn quite as hot? Not quite as much energy delivered to the piston?

 

Oh, when you say mileage, you mean mpg? I'm getting normal gas mileage, same as I've always gotten. typical is 9 to 9.5 liters / 100kms highway driving. Over 10 for city driving, although I don't do much of that. Lemme see, that translates to ...

 

... 23 - 26 miles per US gallon? I've always had this sort of mileage from day one, and it matches the published expected values. If anything I'm getting better mileage lately because I take it easy on the highway these days with the price of gas. (you americans have it good! price of canadian gas is something like $3.75 USD/Gal!) I drive around 70mph on the highway.

 

Anyway, I appreciate any insights. I like to understand how stuff works!

 

Chicobiker

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nope the o2 sensor is in the exhaust pipe. Irt tells the ecu what adjustemnts is has to make in order to have the best combustion. The air flow meter, air sensor, meter (goes by many names) tells the computer the rate of air flow into the engine and its temperiture.

 

60K is way to soon for an o2 or af sensor.

 

Maybe the knock sensor. The knock sensor adjusts ignition timing and that can cause hesitation.

 

 

nipper

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