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rough idle cold

2K views 8 replies 3 participants last post by  saabfan9 
#1 ·
hey guys my 96 aero at start up has a very rough idle after a minute she'll smooth out...no engine light and after seems to run just fine..any ideas? thanks for any help..chris
 
#2 ·
i've had similar problems.
had a small leak in the plastic piece connected to the hose that is right out of the fuel tank.

changed my fuel filter. needs to be done after 150.000 k.

changed temp sensor on engine, its between the second and third fuel injector.

changed sparks for the proper NGK's.

DI module could be bad. they're on e-bay.
 
#4 ·
my swedish girlie runs well now, although cold idle is not perfect yet. but stable. guess they call that character, or charme ;-)

the temperature sensor between the injectors gave the most improvement.
thanks to someone here on the forum, i found it.
if the sensor is not connected, or broken, the engine gets the signal that it is warm all the time. so it wont start. but the sensor has like three steps, or measurements : warm / in betweem / cold. so it could cause your prob too.
 
#6 ·
mine didn't fail till now. but i know from the cars history that it has been changed once. theu seem to last for around a 150.000 km.

i've heard you can notice it, cause it starts difficult, runs on 3 cilinders or rough.

maybe some more experienced forum readers could give this a more accurate follow up ?
 
#7 ·
eerstkoffie said:
the temperature sensor between the injectors gave the most improvement.
thanks to someone here on the forum, i found it.
if the sensor is not connected, or broken, the engine gets the signal that it is warm all the time. so it wont start. but the sensor has like three steps, or measurements : warm / in betweem / cold. so it could cause your prob too.
When mine was wonky, I'd always get the CEL (forget how many flashes). Indie just ripped out the old and plugged in a new one. Ta-da ! :)

I find the fuel octane affects morning 1st cold start idle. With 87 I'd always get some minor stuttering stuttering stuttering :cheesy: (but never dies or anything), but with 89 or higher the smoothness will definitely be there with no roughness.
 
#8 ·
hmmm.... in this country, you can't get any less than octane 95.
but mine is still a lttle rough on cold idle.

it starts right a way, but, once it fires, i have to push the pedal just a little, otherwise it will stop. after like 10 secs running, i can leave the pedal alone. and she runs perfect from then.

character ? ;-)
 
#9 ·
she starts right up (no long crank)..but you can barely make it down the block very crabby and embarassing.. i would say aprox. 2-3 minutes she'll smooth out and not be a problem for the rest of the trip..no check engine light..never dies out just runs like **** ..idle control valve would give a die out at stops...thanks everyone for the help
 
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