PSA car maintenance.

[NL_Fer]

PSA gasoline 1.6 NA: waterleaking head gasket
PSA gasoline Turbo 1.6: Rattling chain
PSA gasoline 1.6 Diesel: ... where do I start?

[strad]

it is a VW Jetta.
Is not a PSA car one of the French group?

[Rodak]

Sorry to sound like a stupid American, but what is a PSA car? I've never heard that expression.....

[Jolle]

Sorry to sound like a stupid American, but what is a PSA car? I've never heard that expression.....

It’s the parent company of Peugeot, Citroen, Vauxhall and Opel.
Bit like you have GM, FCA and Daimler.

[hUirEYExbN]

I would not say it is excessive, no. The lowest I found it when it was checked unprompted, was %30-35ish on the dipstick. Dad said they found it a lot lower a few months ago tho, when he had left it for some unrelated repairs.

What's your engine code? It should be on your info sticker (AKA option label), located in your user manual/info pack. It will be on a sticker with 40 or so 3 character codes. Engine and gearbox codes are usually just below the model and above the big list of codes. If you can't find it, you could go to a VIN decoder and find it that way. To be honest though, topping up oil in a VAG car so infrequently is likely nothing to be concerned about.

Regarding your rougher running, I'd not rely on fault codes (and consequently check engine light) showing up as a failing sensor may not be out of its allowed range of operation yet but could be causing rough running. If you have a code reader you may find pending codes. Do you still get the car serviced? If so I'd suspect a non-service item to be the cause, if there is a cause that is.

O2 sensors are not specified for the life of the car and they certainly don't last forever. They're an easy job but should be fully diagnosed before being changed. Have you noticed fuel consumption change? Regarding fuel smell, is it only when cold or all the time when idling?

As has been said before, plugs (along with coils and leads) could easily cause your rough running. What you describe does sound superficially misfirey.

Anyway, nobody can completely diagnose your issue online for you, but I'm sure there are plenty here who can point you in a direction to work with. There are also many much more suitable forums for this if you want to go the DIY route.

[Shrieker]

What's your engine code?

First of all, thank you for taking the time to write that lengthy reply.

I used to roll my windows during light stops in summer, and yes I got that smell. So probably all the time when idling.

Not exactly sure about the consumption. I didn't really have to drive this car before the corona started.

The O2 sensor issue was diagnosed by a code reader some months ago. There were other error codes as well, but wiping the memory removed them and they didn't pop up in the reader again, except for the O2 sensor fault code. It goes away, and shortly after, reappears. I'm guessing it has to be changed one way or another. Also worth noting, the revs are irregular and it sometimes quits on its own, or worse yet, gives a lot of gas (as if i'm pressing the throttle pedal %50 of the way) on its own, which is scary. The latter has happened rarely over the years (maybe 5-6 times, all of them when the car was cold). This should have something to do with the O2 sensor, right ?

I can't really DIY this, but corona has prevented me from taking it to the repair shop for some time. It's not exactly a car void of any amount of reasonable maintenance, but i feel it has been neglected a bit since the corona started ~a year ago.

When was it's last tune-up?

Idk really. Probably over a year ago. Ditto for air filter, fuel filter and plugs. Either way, once the corona abates a bit, i'll take it to the shop. Meanwhile, I wanted to make sure there wasn't a high probability of imminent failure. Thanks for your tips.

[Big Tea]

What's your engine code?

First of all, thank you for taking the time to write that lengthy reply.

I used to roll my windows during light stops in summer, and yes I got that smell. So probably all the time when idling.

Not exactly sure about the consumption. I didn't really have to drive this car before the corona started.

The O2 sensor issue was diagnosed by a code reader some months ago. There were other error codes as well, but wiping the memory removed them and they didn't pop up in the reader again, except for the O2 sensor fault code. It goes away, and shortly after, reappears. I'm guessing it has to be changed one way or another. Also worth noting, the revs are irregular and it sometimes quits on its own, or worse yet, gives a lot of gas (as if i'm pressing the throttle pedal %50 of the way) on its own, which is scary. The latter has happened rarely over the years (maybe 5-6 times, all of them when the car was cold). This should have something to do with the O2 sensor, right ?

I can't really DIY this, but corona has prevented me from taking it to the repair shop for some time. It's not exactly a car void of any amount of reasonable maintenance, but i feel it has been neglected a bit since the corona started ~a year ago.

When was it's last tune-up?

Idk really. Probably over a year ago. Ditto for air filter, fuel filter and plugs. Either way, once the corona abates a bit, i'll take it to the shop. Meanwhile, I wanted to make sure there wasn't a high probability of imminent failure. Thanks for your tips.

I think he is trying to explain that the sensor code does not mean it is faulty, just that it is not returning the correct response.

For a stupid example, in the dark you sip out of a bottle and say ah, its empty, then put the light on and see there is a cork in it. A code only says the result is not with in the range between limits, not it is at fault (which it may well be)

[hUirEYExbN]

What's your engine code?

First of all, thank you for taking the time to write that lengthy reply.

I used to roll my windows during light stops in summer, and yes I got that smell. So probably all the time when idling.

Not exactly sure about the consumption. I didn't really have to drive this car before the corona started.

The O2 sensor issue was diagnosed by a code reader some months ago. There were other error codes as well, but wiping the memory removed them and they didn't pop up in the reader again, except for the O2 sensor fault code. It goes away, and shortly after, reappears. I'm guessing it has to be changed one way or another. Also worth noting, the revs are irregular and it sometimes quits on its own, or worse yet, gives a lot of gas (as if i'm pressing the throttle pedal %50 of the way) on its own, which is scary. The latter has happened rarely over the years (maybe 5-6 times, all of them when the car was cold). This should have something to do with the O2 sensor, right ?

I can't really DIY this, but corona has prevented me from taking it to the repair shop for some time. It's not exactly a car void of any amount of reasonable maintenance, but i feel it has been neglected a bit since the corona started ~a year ago.

No problem.

A pre-cat O2 sensor failing can and often does lead to rich running. This is not good for the cat so generally should be dealt with as soon as possible. What you describe could be caused by a faulty O2 sensor. However, as Big Tea says, the code is a symptom only, until properly diagnosed. An O2 sensor code could easily be set by faulty wiring or a vacuum leak perhaps even an EVAP issue, EGR issue or any other problem connected to fuel metering and mixture. Also, as you're seemingly getting a misfire (likely rich) then the ignition system (plugs, wires, coil(s)) could do with checking.

Regarding the odd throttle on idle. Depending on engine type, that could be an idle air system or throttle adaptation issue. Adaptation is easy, idle air varies depending on engine type. If it happens again and you feel like it, slowly apply throttle and note what happens when you do. Does the idle return quickly to normal and follow throttle demand, does nothing happen until you have applied "enough" to match the high idle, does it immediately start revving higher. This is good information for your mechanic.

Umm, you're probably fine to use the car until it can be diagnosed and fixed. The only concern I would have is cat life, they like to operate in a pretty strict range.

Anyway, I hope whatever is wrong is dealt with easily and at a reasonable price. One final thing I'd like to suggest, make sure your garage diagnoses the problem before doing work and changing parts.

I think he is trying to explain that the sensor code does not mean it is faulty, just that it is not returning the correct response.

Exactly. Codes are symptoms, not diagnoses.