Shaking engine, rough idle

KEITH11481

MEMBER
2005 CHRYSLER 300
5.7L
V8
2WD
AUTOMATIC
116,000 MILES

My car listed above 300c with a 5.7 hemi will have a shake and rough idle. I am able to disconnect the battery at least for 30 minutes and my car will drive perfect until I go up to highway speed and the check engine light will come on and shaking returns? I can disconnect battery and goes back to driving perfect. I thought it was the PCM, so replaced that but that wasn't the problem. I'm lost and not sure what could cause this and why I can disconnect my battery and problem is fixed until I reach highway speeds?

1 Reply

AL514

MECHANIC
4,795 POSTS

Hello, the check engine light is coming on because the engine computer is seeing a problem and storing a diagnostic trouble code. You need to get the engine computer scanned to see what code is being stored. Thats the reason for the check engine light in the first place. Once you get the code, it will give you an idea of what the problem is. If you go to your local parts store, they should scan the engine computer (ECM) for free. Write down the code and let us know, we can help you diagnose the issue. It sounds like you're having a cylinder misfire issue. The 5.7-liter engines are known for valve lifter issues. So, write all the codes down and come back and we'll help you with testing and further diagnostics.

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

https://www.2carpros.com/articles/engine-misfires-or-runs-rough