2007 Chevrolet Malibu Rough idle

Tiny
KRISTINAWHITE09
  • MEMBER
  • 2007 CHEVROLET MALIBU
  • 3.5L
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 163,000 MILES
Hi and thanks in advance for your help! I recently had a used transmission put in my car and had an o2 sensor wire replaced. When the guy replaced the o2 sensor wire he said he didn't experience any rough idle. I don't have any CEL on. I had a slight rough idle before the o2 sensor wire was replaced but it went away for about 700 miles after the wire was replaced. I had no rough idle whatsoever until yesterday. Now, whenever the car heats up to normal operating temp the car idles very rough and shakes. I just had a tune up (plugs, wires, distributor cap) last summer. Whenever I'm in park or at a stop light it's pretty bad. When I drive at normal speeds, it drives fine. It's really just when I'm stopped. When I put it in reverse this morning it shook worse too. Could it just need new wires?
Tuesday, September 2nd, 2014 AT 5:37 AM

11 Replies

Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
Start out by having the codes read and post the numbers here.
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Tuesday, September 2nd, 2014 AT 6:01 AM
Tiny
KRISTINAWHITE09
  • MEMBER
  • 44 POSTS
There aren't any codes and the CEL isn't on. I may just replace the wires and if that doesn't help take it in and have someone look at it. Was just trying to fix it myself if I could since the plugs and wires are under warranty.
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Tuesday, September 2nd, 2014 AT 6:18 AM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
You could still have codes stored even if the light never came on. It would be very odd to be running that bad and the computer not recognize any issue. It will just make diagnosing it that much harder. Someone on sight is going to have to do some troubleshooting.
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Tuesday, September 2nd, 2014 AT 7:16 AM
Tiny
KRISTINAWHITE09
  • MEMBER
  • 44 POSTS
Do you think a basic OBD II reader would catch a pending code? Or would I have to take it to a shop that has a more detailed scanner?
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Tuesday, September 2nd, 2014 AT 7:55 AM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
It's hard to say. Some generic code reader will show pendings and some won't.
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Tuesday, September 2nd, 2014 AT 1:09 PM
Tiny
KRISTINAWHITE09
  • MEMBER
  • 44 POSTS
Thank you. I'll see if I can pull any codes. I'm also wondering if this could all be related to my used transmission I just had put in. They also put in a torque converter. After driving it for about 8 hours the other day I started it up and heard a whistle noise twice. It hasn't done it since but I read that could be a sign of a bad converter. Also, while driving it today, I was driving between 45-50 mph and it stuttered like it wanted to stall while I was driving. Could all this be related to the converter?
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Tuesday, September 2nd, 2014 AT 2:56 PM
Tiny
WRENCHTECH
  • MECHANIC
  • 20,761 POSTS
A plugged converter is not real likely with those symptoms. They tend to cause more problems at higher RPMs and run better at lower RPMs.

They could have damaged a vacuum line or something on that idea but until somebody on sites gets some idea of what is happening, we have no direction to go.
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Tuesday, September 2nd, 2014 AT 3:42 PM
Tiny
KRISTINAWHITE09
  • MEMBER
  • 44 POSTS
Thanks! We're going to check it out in a day or so. I now have a check engine light on when the key is in the ON position but not when the car is actually on. I'll check the codes tonight.
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Wednesday, September 3rd, 2014 AT 5:33 AM
Tiny
WRENCHTECH
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That would be normal.
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Wednesday, September 3rd, 2014 AT 7:20 AM
Tiny
KRISTINAWHITE09
  • MEMBER
  • 44 POSTS
Yeah, I realized that after I wrote it. I'm still going to check it and see if there are any pending codes that I can get from it. Still going to do the tune up too. Maybe all the wear and tear from my transmission and everything else caused damage to the plugs or wires. Also checking for vacuum leaks just in case. Thanks!
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Wednesday, September 3rd, 2014 AT 8:44 AM
Tiny
KRISTINAWHITE09
  • MEMBER
  • 44 POSTS
Well, we did a tune up and it runs great right now. Unfortunately, I'm not sure if it actually fixed it because last week it did the same thing until I drove it for a while. After I had my O2 sensor wire replaced, it ran great for about 500-750 miles, then started idling really rough again. I think it's because they had the battery cables unhooked for a while and it reset the computer. I'm hoping the same thing isn't happening now (run great for a while then rough idle again) but I guess I'll find out. Any idea what could happen to cause that? (The smooth driving after the computer resets, then back to rough idle). Just wondering in case it does happen again.
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Friday, September 5th, 2014 AT 6:14 AM

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