Cadillac CTS The mid-sized sedan that has grown the popularity of the Cadillac brand with it's low price and sleek styling

2008 cts rough idle

Old 10-28-2014, 02:54 PM
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Join Date: Oct 2014
Posts: 1
Default 2008 cts rough idle

Good afternoon everyone,i have a quick question my 08 cts will have a little rough idle at a stop. no codes or engine light comes on at all, car drives great no issues there. is this normal for a direct injection engine?
Old 11-04-2014, 11:09 PM
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Join Date: Nov 2014
Posts: 1
Default 08 cts rough idle

Did you ever find out if your car had an issue. My car has the same issue. I already did a tune up and problem is still there.
Old 11-05-2014, 07:53 AM
Join Date: Jun 2010
Posts: 210

Hi brahef and BRIPINCH44,

I am sorry to hear that you are experiencing a rough idle while stopped and I can understand how this would be concerning. I understand that you are looking for some feedback from the forum, but have either of you spoken with a dealership regarding this concern? If you are interested in discussing your options with a dealership, please feel free to PM me.

Enjoy your day,

Austin J.
Cadillac Customer Care
Old 06-28-2015, 09:42 PM
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Join Date: Jul 2011
Posts: 2

I've noticed my 08 CTS DI would idle roughly sometimes when stopped. When I mentioned it to the dealer on a few occasions, there was an ECM update available that fixed the issue. Also, using either a gas that has a higher detergent blended in it or periodically using injector cleaner after a fillip helps.
Old 01-12-2017, 11:59 AM
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Join Date: Jan 2017
Posts: 3

I also have a 2012 CTS with a rough/low (550rpm) idle condition
3.0 enigne with 13,000 miles. Have they found a fix for this yet? thanks,
Old 01-30-2017, 09:21 AM
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Join Date: Sep 2016
Posts: 7

I have an 08 also with direct inject and experience the same issue. When Im at a stop of its just idling I hear some vibration coming from the back. Thought my tail pipe might be loose and had the dealership check it at my last oil change and they said it was secure. Been wanting to take it back in to see whats going on. If you find out let us know and Ill do the same.
Old 02-10-2017, 01:24 AM
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Join Date: Feb 2017
Location: Oak View, Ca
Posts: 6

mine also idles but not only when i stop completely. it jerks before i make a complete stop or begin to accelerate. Your engine light should come on. Mine did. But dealer says it may be an ignition coil. can probably mess up your catalytic converter if running lean or rough. Be careful!
Old 08-23-2017, 11:41 AM
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Join Date: Aug 2017
Posts: 1
Default Having similar issues

Hi I have a 2008 Cadillac CTS with direct injection. When stopped the RPMs stay around 550 and idles rough. I'm not sure if these cars just do this normally or if it's something I should be concerned about. I just bought it a few days ago so I'd love to figure it out.
Old 02-13-2018, 09:56 PM
Junior Member
Join Date: Feb 2018
Posts: 1

Had the same problem . You're going to think I'm crazy until you do this...! I changed all my ignition coils and spark plugs then cleaned my throttle body. No fix! I remembered an old mechanic's advice about an old Ford Ranger I owned 20 years ago and I drove my CTS for roughly 5 miles in 2nd gear at 4,000 RPMs. My borother-in-law is a mechanic and said it was an epiphany moment. It fixed all the rough idle and vibration issues I was having! Try this before doing all the parts swaps! Let me know if this helps you. If you're not sure, call me at (252)764-1781. I'll be glad to talk to you about it .
Old 04-28-2018, 06:04 PM
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Join Date: Apr 2018
Posts: 6
Default 2008 Cadillac CTS 3.6L DI rought idle

Has anyone gotten a good answer to this question? I also have a very rough idle at a stand still. I've had the sparkplugs and valve cover gaskets along with the upper intake gaskets changed. I've also had the EVAP purge solenoid valve as well as the O2 sensor, I matain regular oil changes and maintenance but cant figure out why the idle is rough. I even had the motor mounts looked at thinking that may be the issue but still no luck. Someone please help!

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