Thanks Shep,
>
> what is the "egr" stands for?
>
> Shep wrote:
>> Look for a vacuum leak, or the an egr not seating properly, these both
>> affect idle quality, other things can do this, but start with these.
>> > This is a fairly old GMC Chev Cavalier with a 3.1 MFI V5 engine. >> >
>> > The car start behevour differently from about 2 months ago, the main
>> > thing is that all the light (headlight, interiorlight, panel light, et
>> > al)go up and down at about 1 Hz. It always do this when the car was
>> > started from cold, and sometimes, it goes away within about 5 min of
>> > driving, and sometimes it stay that way for 20 to 30 min. It come up
>> > less often when the car is warm.
>> >
>> > When the lights go up and down and the car is at idle, the engine speed
>> > fluctuate within 200-300 rpm (both cold and warm).
>> >
>> > It appears that the lights fluctuation is due to the engine speed no >> > stable.
>> >
>> >
>>
>>
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