Hyundai Elantra is throwing a tantrum

[Used2Race]

My gf got a 2018 Hyundai Elantra. She got it for around three years and took care of it well. Lately, it's been idling roughly and the RPMs drop low, especially with the AC on. Yeah, the car even shakes a bit.

I'm driving it today, bcs she needed a better car to drive to the next city. there's this quick little jerk sometimes, but it's smooth over 40 mph.

I thought about cleaning the throttle body, but I want to ask people here first before I do that.

If anyone's dealt with this before and got it fixed, tell me what else I should check other than the throttle? please throw me a bone!

 

[Diamonds]

Okay if you've never done it, cleaning the throttle body is such a bad way to start but you could also check the idle air control valve if it has one (some models don't), and vacuum lines for any leaks, cos these two things can really mess with idle big time.

 

[grayle7]

Agree with Diamonds here. A dirty or faulty sensor can also mess with RPMs. Have you looked at spark plugs or engine mounts too? Hope you find a fix soon!

 

[ElantraLlama]

Great suggestions. I had a similar issue with my old Corolla, it would idle roughly when the AC was on, and I felt slight jerks at low speeds, but it would smooth out once I hit 40. I thought it was the throttle body too, but it turned out to be a tiny vacuum leak in a cracked hose.

You should definitely take a look at those vacuum lines, and maybe check the plugs while you're at it. Cleaning the throttle body isn't a bad idea either, especially if it hasn't been done before. Did you happen to hear any strange hissing sounds while it's idling?