My 2001 Daewoo has a rough idle after.

Tiny
GS966
  • MEMBER
  • 2001 DAEWOO LANOS
  • 73,000 MILES
Hi, my 2001 daewoo has a rough idle after sitting a while(overnight for example). It shakes and studders a lot. Sometimes the car stalls and I have to press the gas pedal in order for the car to keep running. After it warms up it runs well but can still feel a little shaking at idle. I changed the iacv, tps, air temp sensor, engine coolant temp, and map sensor. Please help.
Sunday, December 30th, 2012 AT 4:33 AM

9 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Ok, you replaced stuff that has nothing to do with your issue.

How about plugs/wires/coils? When did you last change the timing belt.

Roy
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Sunday, December 30th, 2012 AT 5:13 AM
Tiny
GS966
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I also replaced those when I first got the car, which was about 7-8 months ago; spark plugs, wires, and coil. I also replaced timing belt and fuel pressure regulator. Also, there is this wining noise, I can hear it from inside the car but I can hear it better from the rear of the car near exhaust.
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Sunday, December 30th, 2012 AT 2:39 PM
Tiny
KHLOW2008
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  • 41,814 POSTS
Have the engine compression tested. Do you have overheating and coolant losses issues?
Check the valve clearances as well.
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Sunday, December 30th, 2012 AT 6:59 PM
Tiny
GS966
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No overheating but I do have coolant loss. But it looks like it's leaking from thermostat housing area. I'll test compression but how would I check valve clearances and what is that?
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Sunday, December 30th, 2012 AT 7:04 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
I believe your engine is equipped with automatic valve lash adjusters so you need not do anything about them.

If your engine had overheated previously, it could have resulted in damage to the head gasket that is causing compresison leaks and would affect cold start and idling issues.

Did you clean the throttle body?
Was IACV new or used unit?
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Sunday, December 30th, 2012 AT 7:14 PM
Tiny
GS966
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I put in a used, but clean throttle body and iacv is new. I'm not sure if the engine overheated but I do know that timing belt jumped on the previous owner and when I took it apart I saw that one of the lifters were bad so we replaced it. Before we replaced it would barely run. Head gasket recently blew so that was changed also.
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Sunday, December 30th, 2012 AT 7:22 PM
Tiny
KHLOW2008
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Were the valves lapped when the head was removed?
A minor leak in compression would show the symptoms described. Btw when testing the compression, do it under cold conditions to be accurate as problem occurred then.
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Sunday, December 30th, 2012 AT 7:28 PM
Tiny
GS966
  • MEMBER
  • 5 POSTS
Ok, thanks. The valves were not lapped.
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Sunday, December 30th, 2012 AT 7:57 PM
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Let us know how it goes.
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Sunday, December 30th, 2012 AT 8:03 PM

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