Did I buy a lemon?

[RaidingTurtle]

I just bought a 2011 Elantra with 168000 miles on it. I need a dependable car and was sick of always making car payments, so I bought this one from a “car auction” type lot where I could afford to purchase one without needing to finance it.

It drove good, but on the way home from the lot, it started having a rough idle, and the check engine light came on.

I took it to a mechanic I trusted, and he said the engine code was for a crank case sensor. I paid about $400 to replace the sensor yesterday. Then last night when I was driving and once again it started idling rough, and the check engine light came back on.

I like the car, and would prefer to fix whatever the issue is rather than trying to get a refund and start shopping again. But, I can’t be throwing away 3-499$ constantly chasing an issue.

I am worried about the check engine light, and the rough idle though. Would fuel additives help? I filled the car up yesterday with premium fuel before the engine light came on (and I made sure to tighten the gas cap!

[Stealthee]

It's not a lemon because its a used car that is 14 years old.

No one is going to be able to tell you what is wrong with the car without doing diagnosis. Fuel additives aren't going to help, and neither is premium fuel.

Don't be shocked if you don't get a "refund" because that's not how car buying works.