what makes my car start with rough idle at first?

1988 CHEVROLET BERETTA
240,000 MILES
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BARRY724
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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?
Apr 15, 2012 at 8:22 PM
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ASEMASTER6371
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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
Apr 15, 2012 at 8:25 PM
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BARRY724
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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?
Apr 15, 2012 at 10:10 PM
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ASEMASTER6371
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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
Apr 16, 2012 at 12:31 AM
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BARRY724
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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.
Apr 16, 2012 at 12:38 AM
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ASEMASTER6371
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i dont believe they do free code checks on obd 1 systems. it is a completely different system.

try the plugs and see.

Roy
Apr 16, 2012 at 12:39 AM