Lori and the Check Engine Light

[Lorizael]

Class and TAing all day, work all evening, homework and papers when I should be sleeping, sleeping at red lights, and now somehow I have to find time to deal with car problems.

So I got an oil change a few weeks ago. Afterward, the car smelled like burning oil and the check engine light came on. Some googling told me maybe they spilled oil and that was burning off and it was no big deal. But it didn't stop, and the check engine light was still on, so I took my car to the mechanic (different place than the oil change). Oil change people forgot to put the ****ing oil cap back on and there was ****ing oil all over the place under the ****ing hood. Mechanic cleaned that all out and cleared the check engine code.

27.962 miles after that, the check engine light came back on. Mentioned this at D&D session, and one of my players hooked up his little engine monitoring gizmo to my car and found that the O2 sensors had detected something wonky with the fuel/air ratio (codes P0171 and P2097). More googling told me this could be a result of a couple things and that rough idling and engine hesitation might be symptoms. Those are symptoms I've had for awhile but ignored because I'm bad at owning a car. Took car back to the mechanic. They tried replacing one of the O2 sensors but that didn't help and recommended I take the car (Mazda 3) to the dealership to diagnose.

Which I guess I will do... some time before I die... but possibly not before I graduate... although the way things are going now I might die before I graduate. (Like, I'm going to graduate in 3 weeks, and nothing is going to ****ing stop me, but I might be a literal ****ing zombie at commencement.)

Anyway, does anyone on Poly have any idea how cars work? Or can you offer a bull**** opinion that sounds good? Thanks.

[giblets]

Aren't you glad you don't drive an electric car?

[Lorizael]

I'd be even poorer if I owned an electric car.

[N35t0r]

The lambda probes (oxygen sensors) measure the oxygen concentration in exhaust gases. Too much oxygen means the fuel/air mixture is too poor (lean), which makes the car a bit more sluggish and hotter. Too little oxygen and the mixture is too rich, which means unburnt hydrocarbons leftover from combustion and increased fuel consumption.
Both cases mean less power output.

Without knowing wtf those codes mean, or getting near your car, I don't really know what to say (it's also been ~8 years since I worked on cars).

How would you describe your idling issues? Take into account in wtfforeign and don't have any car lingo. Since both a too poor and a too rich fuel mixture can cause (different) idling issues.

Also, mandatory "did you check your oil level?".

[N35t0r]

Also, lol that a mechanic's first option is to take it to the dealership.

[rah]

You did the right thing.
When the check engine light comes on, take it to a car parts store that will do the check for free. (in the hopes of selling you the part to fix an issue).
Listen to what they say is a possible problem but ask them for the error code. Go home google research it for possible issues. And this seems what you did.
And if they sound like they're bsing you, just go to a different place to see if they say the same code and fix. There are about 10 places within a few miles of me that will do that.

In my experience this will help you about 50 percent of the time.

Once it said I needed a simple sensor replaced which I bought for 35 bucks form them and had my local mechanic replace for 20 bucks.
The dealer had quote a 250 dollar fix. Screw them

The next time it was a misfire error code on cylinder 1 and the guy at the auto parts place told to switch out the ignition coils on cylinder 1 and 2 and bring the car back and if the error code showed a different cylinder was misfiring, to just buy a new ignition coil and replace it. Since cars a considerably more complicated than when I would attempt crap when I was younger I just kind of gave him the deer in the headlight look. He noticed it and started laughing and said, just google and watch any of many utubes and it was real simple to do. I did and it took me about 2 minutes to switch them out. Went back and that was indeed the problem and the new coil was only about 20 bucks and I fixed it myself. Definitely saved money on that one.

But I've had a couple of times where the code was more ambiguous and a few quick tries didn't do anything, so I had to bend over for the dealer.
It never hurts to do a little investigating before turning your car over to the dealer, and if nothing else it's makes it a little harder for the dealer to really screw you if they know you had the code checked first. It's not like they can tell you they need to replace the tranny when the error code was for a co2 sensor failure.

[N35t0r]

Oxygen sensor

[rah]

If the state you live in does emission testing, that code would fail the car automatically.

[Lorizael]

The lambda probes (oxygen sensors) measure the oxygen concentration in exhaust gases. Too much oxygen means the fuel/air mixture is too poor (lean), which makes the car a bit more sluggish and hotter. Too little oxygen and the mixture is too rich, which means unburnt hydrocarbons leftover from combustion and increased fuel consumption.
Both cases mean less power output.

Without knowing wtf those codes mean, or getting near your car, I don't really know what to say (it's also been ~8 years since I worked on cars).

How would you describe your idling issues? Take into account in wtfforeign and don't have any car lingo. Since both a too poor and a too rich fuel mixture can cause (different) idling issues.

Also, mandatory "did you check your oil level?".

Idling issues: car periodically rumbles and RPM drops.

Hesitation issues: Does not accelerate smoothly at all, and when cruising on the highway, the engine will sporadically do this thing where for like a quarter of a second it feels like I'm not pressing the gas anymore and then go back to normal. This has been getting worse (mostly in terms of frequency).

[Lorizael]

If the state you live in does emission testing, that code would fail the car automatically.

Thankfully I passed relatively recently and don't have to do that again for awhile.

[N35t0r]

Idling issues: car periodically rumbles and RPM drops.

Hesitation issues: Does not accelerate smoothly at all, and when cruising on the highway, the engine will sporadically do this thing where for like a quarter of a second it feels like I'm not pressing the gas anymore and then go back to normal. This has been getting worse (mostly in terms of frequency).

That seems to be an issue with the injectors and/or spark plugs.

[Proteus_MST]

Check Engine Lights don't matter to anyone, except Sheldon ... ask Penny (from TBBT)

[N35t0r]

It could also be your air mass sensor. That's probably the easiest thing to replace (and is more likely to fail and give such an error)

Do you have your air filters changed with the oil change? Take a look at it. It should be easily removable.

[Lorizael]

Do you have your air filters changed with the oil change?

Probably not? As I said, I'm very bad at car ownership.

[Ben Kenobi]

O2/C02 sensors are the likely culprit, also, how are you closing your gas cap? I had (have, and been having) a similar issue. Took the car into a mechanic and they checked it out and said the car was fine otherwise.