"Engine and transmission works good. Check engine light on. Car runs and is drivable. Needs a tune-up service. Clean title . Asking $1000 Firm"

Guy says it runs rough at low speeds, but doesn't stall. What's the worst case scenario with this? He sounds like a bit of a mechanic, and doesn't want to deal with it, says it is very technical.

What could be wrong if someone's run 87 gas in it for a long time?

 

+ it's an automatic.

 

Is the head gasket usually a quick replacement or do they get warped?

 

Head gasket isn't a quick replacement.
Rings go out frequently on those which is why the majority of them smoke.
The 3.5L swap is common in those, well it used to be but not any more because not very many of them are on the road anymore.


I hate to say this, but those cars are junk for the most part. The engines are junk, the transmissions aren't that much better, and even the coveted Type II engine is sort of a piece of crap.

Back when they were newer with less miles I'd buy one in a heart beat, but now that they're 20+ years old with a lot of wear and tear, I wouldn't take one if it was given to me for free.

 

That's pretty accurate unfortunately. I'd like to have one, but when you look around at the other vehicles you could pick up for the same money as a 20 year old legend with 120k miles that's famous for head gasket failure it makes zero logical sense to buy a legend.