What makes my car start with rough idle at first?

Tiny
BARRY724
  • MEMBER
  • 1988 CHEVROLET BERETTA
  • 240,000 MILES
After car has been sitting for more than an hour or two it cranks with a rough idle then smooths out normally. It does not miss thru driving and runs good overall.I had new plugs and wires and ignition control module put in 6 months ago.I do not hear any vacuum leaks. Maybe a new air filter will help or may go get some bosch plus 4 plugs to see if it helps. Will a diagnostic check show anything?
Sunday, April 15th, 2012 AT 8:22 PM

5 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Not on an 88. Obd 1 is a very limited system for codes.

Do you use any oil or coolant? I am thinking that maybe a plug or 2 gets coolant or oil on it and it misses till the cylinder heats up.

Roy
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Sunday, April 15th, 2012 AT 8:25 PM
Tiny
BARRY724
  • MEMBER
  • 11 POSTS
Yes I use oil and coolant and do not have significant leaks but may take plugs out and clean or replace them.I did notice the top of a plug or two are black don't know if they are supposed to be I assume they should be silver I just noticed when taking plug wire off. My mechanic suggested I take brake cleaner and clean mass airflow where it connects to engine?
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Sunday, April 15th, 2012 AT 10:10 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
Nope, mass air flow will not do it. I do not believe in cleaning a mass air flow. The carbon is burned on to the tip and cannot be cleaned off with any type of cleaner.

Roy
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Monday, April 16th, 2012 AT 12:31 AM
Tiny
BARRY724
  • MEMBER
  • 11 POSTS
I think new plugs will help.I see what you are saying about coolant and oil ASEMaster6371.I think it probably is in the ignition maybe but I am only guessing. Since I had a new ignition control module put in I am discounting this but it could be bad.I do have a warranty on this for 1 year. So I may get the same place to check it out but there is no "check engine " light coming on but can they tell me if they hook it up to the computer.I think I will try new plugs 1st.I have maintained this car for years and runs great so I will keep on digging.
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Monday, April 16th, 2012 AT 12:38 AM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,796 POSTS
I dont believe they do free code checks on obd 1 systems. It is a completely different system.

Try the plugs and see.

Roy
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Monday, April 16th, 2012 AT 12:39 AM

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