2013 Accent mileage starting to tank

Hiya, new to the forum.

I'm pretty good at working on cars. Restored and repaired my 1970 Chevelle. Converted my 1985 CJ7 to fuel injection. But honestly I've done very little to my Accent. I don't know a lot about the newer generation cars.

I'm about 150,000 miles on a California vehicle. I've done oil and filter regularly. I've also replaced the plugs twice and the air filter as well, but that's about it.

Lately my mileage has gone from 35-37 down to the high 20's. I'm sure something is wearing out and needs to be replaced and I'm hoping some of you can pipe in and let me know what to look for.

And yes, I'm expecting some "You've got 150k miles and you've never changed the <insert obvious part here>???"

Thanks for your time.

 

I replaced the fuel injectors on my 150k Honda Odyssey. Gas mileage was not great but it's much better now and acceleration is better too. Same great stuff with my 140k Nissan 240sx.