Intermittent hard to start?

Tiny
JOHN KUNZ
  • MEMBER
  • 2016 KIA OPTIMA
  • 2.4L
  • 2WD
  • AUTOMATIC
  • 101,057 MILES
Hey everyone, I could really use some help.

I drive the vehicle listed above EX with about 101,057 miles on it. Lately, I’ve been experiencing a strange issue with starting. Here’s what happened today:

I turned off my car like normal, and then about 3–4 minutes later, I tried to start it again. It sputtered and didn’t fully start, almost like it was about to die or run out of gas — but I have a full tank. I tried putting it in drive, but it wouldn’t move. So, I turned it off, then hit the start button again, and this time it started right up like nothing happened.

This has actually happened multiple times over the last few weeks. Sometimes, when I go to leave work or the grocery store (like today at Winco after 20 minutes inside), it’ll hesitate or take 6–7 seconds to crank. It feels sluggish, kind of like a chugging or sputtering start. Other times, it starts normally.

Today it was 92°F outside, but it’s done this in various conditions.

Here’s what I’ve already done:
• Took it to AutoZone: They tested the battery, starter, and alternator — all passed.
• Took it to O’Reilly Auto Parts as well for a second opinion — also said everything looks good, and connections looked clean (no corrosion).
• Ran the Fix Finder diagnostic at AutoZone — no codes or issues showed up.
• No check engine light has ever come on during any of this.

I’m at a loss. I don’t want to get stuck in an emergency or be late to something important and have it fail completely. It’s hard to diagnose when it only acts up occasionally. I just want to understand what could be causing this and what I should check next.

Has anyone dealt with something like this before? Any ideas or suggestions?

Thanks in advance — I appreciate any advice.
Thursday, July 17th, 2025 AT 5:26 PM

1 Reply

Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,137 POSTS
Yep, I have seen two causes for this, one is the throttle body needs to be serviced, here is a guide to show you how with instructions below for your car.

https://www.2carpros.com/articles/throttle-actuator-service

Also, it can be a high-pressure fuel pump starting to go out or you have a vacuum leak. Let's check for the vacuum leak first. Go over this video to see who to check:

https://www.youtube.com/watch?v=LRKWV4Are5c&t

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Thursday, July 17th, 2025 AT 5:38 PM

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