90 S4 low idle, dies sometimes at stop
02-08-2010, 01:38 PM
#46
Racer
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Join Date: Jul 2009
Location: Byhalia, MS
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Since then, I put about 7000 miles on the car and then the surging began again.
This time the surging was getting steadily worse. I never disconnected the battery until I started troubleshooting it with you guys. The only difference between this time and last year is that I changed the O2 sensor. I have my fingers crossed too!!
Keep me posted...
02-08-2010, 04:52 PM
#47
When the car is cold it cranks fine and idles around 650 as it should.
Once the car warms up the idle will drop to around 600 rpm and its rough.
As you slow down for a stoplight, you can feel the engine surging as you come to a stop. At the light, there is a surge to the idle and sometimes the car dies. If you put the car in neutral and hold the rpm at 1000, you can still feel the surging going on. It is not enought to vary the tach but you can still feel it. You can sometimes see the voltage needle swinging a bit and the oil pressure swinging with the surging.
The car accelerates normally and runs smooth at speed. Any suggestions on this one?
Once the car warms up the idle will drop to around 600 rpm and its rough.
As you slow down for a stoplight, you can feel the engine surging as you come to a stop. At the light, there is a surge to the idle and sometimes the car dies. If you put the car in neutral and hold the rpm at 1000, you can still feel the surging going on. It is not enought to vary the tach but you can still feel it. You can sometimes see the voltage needle swinging a bit and the oil pressure swinging with the surging.
The car accelerates normally and runs smooth at speed. Any suggestions on this one?
