RPM's surge only when engine is warm

IKE13

MEMBER
2001 SATURN SC1
1.9L
4 CYL
2WD
AUTOMATIC
156,600 MILES

This problem just started about one week ago. Whenever I am stopped and my engine is idling and only while it is running at normal operating temperature does it surge. When its cold it does not have this problem. I had it tested at an auto parts store and the code that reads is P0340 camshaft position sensor A. Is this the cause of my rpm's surging?

Saturday, December 2nd, 2017 AT 10:10 PM

5 Replies

JIS001

MECHANIC
3,411 POSTS

That would not cause the surge. I would recommend you clean the idle air control valve or replace it.

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Sunday, December 3rd, 2017 AT 2:16 AM

IKE13

MEMBER
12 POSTS

I already cleaned and replaced that valve. That worked for the RPM's spiking to 3000 RPM's on start up and accelerating by itself. It just seems odd that it only does it when the car is hot.

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Sunday, December 3rd, 2017 AT 5:27 PM

JIS001

MECHANIC
3,411 POSTS

Check for a vacuum leak. If no leak then I would just replace the idle air control valve.

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Sunday, December 3rd, 2017 AT 6:16 PM

IKE13

MEMBER
12 POSTS

I promise you it's not the IAC valve or vacuum leaks. And it only does it while the car is hot

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Monday, December 4th, 2017 AT 9:42 PM

KEN L

MASTER CERTIFIED MECHANIC
51,757 POSTS

I would try the camshaft sensor since it has a code for it. Here is a guide that will show you what you are in for when doing the job.

https://www.2carpros.com/articles/camshaft-angle-sensor-replacement

Please let us know what you find.

Cheers, Ken

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Thursday, December 7th, 2017 AT 6:36 PM