1999 OLDSMOBILE ALERO IDLES ROUGH AND NOT ON ALL CYLINDERS

  • Tiny
  • Quartermilecamel
  • 1999 OLDSMOBILE ALERO

Engine Performance problem
1999 Oldsmobile Alero 4 cyl Front Wheel Drive Automatic 84000 miles

Hello, I am working on a 1999 olds alero with the 2.4L in it (quad 4 engine). It doesnt run on all 4 cylinders. Ive never worked on one of these engines before. Im not even sure how to tell which cylinders are not firing or if the cause is fuel or fire. I pulled the plugs and they all look light tan. So none of the plugs are black or have signs of not firing, as far as I can tell, so that doesnt help. No check engine light noted. Autozone or advanced auto can test the ignition modules but I dont know how much stock I would put in that. The car has 83,000 miles on it. I checked to see it has coolant in it and it does have the dex cool red crap in it. Tail pipe finger test produced typicial black soot on the finger. Im not sure what a blown head gasket would look like on plugs with dex cool coolant.

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Sunday, August 24th, 2008 AT 5:28 PM

5 Replies

  • Tiny
  • Mastertechtim
  • MEMBER

These engine dont typically blow head gaskets. Engine misfires are usually caused by a faulty ignition coil cover. Thats the housing that the plug wires connect to. It acts like a distributor cap and distributes spark to cylinders and sometimes they arc out inside

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Sunday, August 24th, 2008 AT 5:37 PM
  • Tiny
  • Quartermilecamel
  • MEMBER

So If I were to take off the coil tower, would I see evidence of arc over?

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Sunday, August 24th, 2008 AT 5:48 PM
  • Tiny
  • Mastertechtim
  • MEMBER

No. Even on good coil covers you will see arc marks, you just have to feel that it is a ignition skip and then replace it

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Monday, August 25th, 2008 AT 7:29 PM
  • Tiny
  • Quartermilecamel
  • MEMBER

Replaced the cover and one coil. Car runs fine. One coil measured 9 million ohms across the secondary terminals, the other coil measured 50 k.

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Monday, September 8th, 2008 AT 12:20 AM
  • Tiny
  • Mastertechtim
  • MEMBER

Awesome

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Thursday, September 11th, 2008 AT 5:37 AM

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