Let me explain what has happened; it is very peculiar due to the sequence of events.
My car was serviced a month ago, with everything updated that was slightly old or worn out. My car is 10 years old and in fairly good condition.
Two weeks ago, my check engine light came on once my gas tank hit 1/4 fill. I went and got gas, and it turned off immediately after.
It had not come back on until today, when my gas tank hit the 1/4 mark yet again. I do not drive a lot due to living in close proximity to school and work. I went and filled up my gas tank yet again, and the check engine light, this time, stayed on.
Now, I know my gas cap is not very tight but it DOES click and lock in place. Might this be the reason?
I find it very difficult to fathom that there could be something fundamentally wrong with a car that was just completely serviced (with the exception of the brakes, which do NOT set off the check engine light) a month ago, without them noticing anything wrong.
I also think it must have something to do with my gas, since it only went off last time when I got gas, even though that didn’t turn it off this time. I wonder if it has something to do with the gas cap and by coincidence, it locks out of place. I know when I went and got gas today, it came off almost instantly upon turning it, which it shouldn’t… even though other times it locks in place just fine.
My check engine light came on a couple of months ago, and went off after filling up. I ignored it therefore, and ignored it when it came back on and ignored it when I got my oil changed and it stayed on.
So last Sunday, as I was driving to a friend’s house in 85-degree heat, with my 5-year-old in the car, I felt real stupid when my car died: the engine would turn over and then sigh asleep after about two seconds. I was able to pull into an abandoned lot and eventually get someone to come pick us up; if it had died on the interstate, things could have been very hairy.
The tow truck driver was certain it was the fuel pump, that I’d pay $500. Fortunately, he was horribly wrong.
It was rats.
A rat (or some other critter, I prefer to imagine it was an adorable woodland mouse) made a nest out of my air filter. Over the course of weeks, bits of the chewed-up filter, as well as pieces of gravel and other detritus, made their way into the air intake valve of my car, until the valve was clogged. $50 later, the filter was replaced, the intake was cleaned, and the light was off.
Which is all a long way of answering your question of what could do this to your car: rats, maybe?
Replace the gas cap - it MIGHT be the problem, and its cheaper than a diagnostic OBD reader (which is a good investment if you plan to keep an older vehicle).
If the cap doesn’t solve the problem (use a cheapie to test - and keep it handy if you lose the locking one).
If the cap does not resolve it: there is a white trapezoid socket under your dash (some hide it behind the ash tray). A OBD reader plugs into it and tells you what is wrong.
Readers start about $60.
Cheaper than the mechanic.
In CA 8 years ago (haven’t looked since) mechanics were charging $80 to read the OBD. I did see some saying “Applied toward bill if repairs made here” or such.
There’s literally hundreds of things that can cause a check engine light to come on. No automotive service is comprehensive enough to find everything that may cause the CEL to come on in the near future.
As far as why the light came one, go to somewhere like Autozone where they will read the CEL codes for free. That may, or may not, point you in the direction of the problem. The CEL code is just the first step in finding the problem. More troubleshooting is required.
As the issue first happened around a forth of a tank, I’d guess fuel pump or maybe something in the evaporation emissions system. Just a guess.
Does anyone think any of the seemingly likely possibilities are detrimental if I ignore it for another week or two? I drive my car no more than 5 minutes per day, and I have no time nor means to get to a mechanic or the car dealership.
The CEL is about the emission control system - not anything central to the operation.
So driving it short distances MAY be harmless- you’re just polluting a bit more than usual.
Unless it IS the fuel pump and it is giving up a free head’s up before it dies completely.
Auto zone in CA stopped giving free diagnostics after getting a nastygram from the State - the mechanics who were charging $80 did not appreciate the competition. Don’t know if they have resumed.
Autozone was selling readers which cost $60 at the time. The State didn’t object.
Do not ignore this. Misfire can destroy you catalytic converter in short order.
If the check engine should start to flash it means fix it NOW, NOW, NOW. No more driving.
Depends on the cause and the shop.
Misfire causes include:
[ol]
[li]Spark plug [/li][li]Spark plug wire (if your car is so equipped) [/li][li]Distributor cap (if your car is so equipped) [/li][li]Distributor rotor (if your car is so equipped) [/li][li]Individual coil for spark plug (if your car is so equipped) (probably is) [/li][li]Bad fuel injector Clogged fuel injector problem inside the cylinder.[/li][/ol]If your shop can’t do all six, shop for a new shop.