My car jerks and my idle surges?

JAS0822

MEMBER
2007 KIA SPECTRA
2.0L
4 CYL
2WD
AUTOMATIC
107,970 MILES

I finally got a new car, and something started happening today. When I’m driving it does fine, but when I stop at a light or a stop sign, my car jerks and my idle surges and like bounces up and down. Someone tested my throttle position sensor, could that be it? They unplugged it while running in park and my idle didn’t change at all. Thanks in advance.

3 Replies

KEN L

MASTER CERTIFIED MECHANIC
43,332 POSTS

Yes, the TPS can cause that, but we should run the codes to see what comes up. also, I have seen a dirty throttle bore or a vacuum leak cause this issue. so, let's go over these guides to help us fix the problem:

https://www.2carpros.com/articles/checking-a-service-engine-soon-or-check-engine-light-on-or-flashing

Use this guide when the engine is cold only:

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

This guide to help service the throttle body:

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

Please go over these guides and report back.

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Friday, March 3rd, 2023 AT 10:44 AM

JAS0822

MEMBER
64 POSTS

So, there are no codes, and I just replaced the TPS because it wasn’t too much money. I noticed that the cold start RPMs changed. Before when I started my car on a cold start it idled at about 2000 rpm’s and now on a cold start it’s between 1,000 and 1,500 RPMs. I’m going to drive it tomorrow and see what that does.

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Friday, March 3rd, 2023 AT 4:46 PM

KEN L

MASTER CERTIFIED MECHANIC
43,332 POSTS

It could just need to relearn which can be done by just driving it. Here is some information on the TPS sensor in the images below. Please let us know what happens.

Images (Click to make bigger)