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Engine misfire cylinders?

Tiny
1999SL2
  • MEMBER
  • 1999 SATURN SL2
  • 190,000 MILES
The car abruptly began to misfire, on the highway, with loss of power and vibration. It was turned off for refuelling, turned back on, and continued to misfire. After a five minute drive, it cleared itself for 5 minutes, was shut off, but resumed the same symptoms upon restarting. Codes P0300, P1599 and P1555 (previously registered, have not replaced EVO) registered. Followed advice to disconect plug wires, with engine running. Disconnection of #2 and #3 resulted in no change. Replaced O2 sensor for Bank 1 Jan 2011.
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Saturday, January 28th, 2012 AT 12:24 PM

57 Replies

Tiny
1999SL2
  • MEMBER
  • 9 POSTS
And the exhaust smells as if it has a lot of unburned fuel. Maybe the downstream O2 sensor has died, so the ECU is cutting spark to cylinders 2 and 3?
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Saturday, January 28th, 2012 AT 12:55 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
No a o2 sensor would not cut out two cylinders bad or not check for spark on number 2 and 3 cylinders.Let me know if you have spark on those two and we will go from there.If you have spark then we need to check compression.Only three things really tie those two cylinders together spark same compression stroke and fuel injectors firing.My money is on spark first then compression issue. this guide can help us

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Please run down this guide and report back.
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Saturday, January 28th, 2012 AT 2:14 PM
Tiny
1999SL2
  • MEMBER
  • 9 POSTS
I checked spark with the 3rd from left plug against the header. No spark. Are the coils the next thing to check? Is there an easy way to swap them?
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Sunday, January 29th, 2012 AT 4:20 PM
Tiny
1999SL2
  • MEMBER
  • 9 POSTS
Voltage on the battery when running is over 14.2, also.
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Sunday, January 29th, 2012 AT 4:28 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
You can swap the coils from left right to right you jut have to take the four bolts out see if the no. Spark follows the coil. Let me know what you find.
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Sunday, January 29th, 2012 AT 5:14 PM
Tiny
1999SL2
  • MEMBER
  • 9 POSTS
I swapped the coils, left to right, marking the original left, and the misfire still occurs on #2 and #3 cylinders, confirmed by disconnecting spark and injector wires. Still smells like gas. As you face it, the left coil feeds cylinders 1 and 4. The ignition control module didn't have anything visibly wrong with it.
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Monday, January 30th, 2012 AT 5:53 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Are you getting spark from the number 2 and 3 cylinders?If not then you have a bad ignition module. Let me know what you find.
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Monday, January 30th, 2012 AT 5:57 PM
Tiny
1999SL2
  • MEMBER
  • 9 POSTS
Yesterday, I pulled the #3 spark wire and grounded it against the header: no visible spark, with the engine cranking.
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Monday, January 30th, 2012 AT 6:04 PM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
If you have spark on the number 1 and 4 cylinders and not on the number 2 and 3 cylinders and its not the coil then the only other thing left is a bad ignition module.
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Tuesday, January 31st, 2012 AT 4:50 AM
Tiny
1999SL2
  • MEMBER
  • 9 POSTS
Thank you!
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Tuesday, January 31st, 2012 AT 6:29 AM
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Keep me posted on how it goes.
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Tuesday, January 31st, 2012 AT 6:40 AM
Tiny
1999SL2
  • MEMBER
  • 9 POSTS
I bought a new ignition module, installed it and that did the trick, but not the idle is high and erratic. I removed and cleaned the spark plugs and removed and wiped off the O2 sensor on the header, figuring that the plugs and sensor might have gotten fouled with unburned fuel. No joy. Is there another valve/sensor that would have been fouled by the unburned fuel, or do you have other thoughts?
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Saturday, February 18th, 2012 AT 11:10 AM
Tiny
SATURNTECH9
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What codes do you have now?How high is the car idling?How many rpms?What kind of spark plug do you have in the engine?Not platnuim ones I hope?
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Saturday, February 18th, 2012 AT 4:23 PM
Tiny
1999SL2
  • MEMBER
  • 9 POSTS
No check engine light, yet. 2000, but up to 3000, sporadically. Stock Saturn dealer ones (?)
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Saturday, February 18th, 2012 AT 4:39 PM
Tiny
SATURNTECH9
  • MECHANIC
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With that high of a idle I would check for vacuum leaks first.
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Saturday, February 18th, 2012 AT 10:14 PM
Tiny
MYSELF1168
  • MEMBER
  • 2 POSTS
  • 1999 SATURN SL2
  • 150,000 MILES
Okay so I'm having an issue with the cylinders 1 and 4 not firing, they are on the same coil. I've switch coils and they still don't fire. I've also switched out the ignition control module, and still 1 and 4 are not firing. I am at a loss for what should be checked next. Thanks in advance.
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Friday, September 25th, 2020 AT 10:08 AM (Merged)
Tiny
MYSELF1168
  • MEMBER
  • 2 POSTS
Also it is not sparking from/at the coil so its not wires or spark plugs.
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Friday, September 25th, 2020 AT 10:08 AM (Merged)
Tiny
MHPAUTOS
  • MECHANIC
  • 31,937 POSTS
Scan for a crank angle sensor fault check for power at the coils.
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Friday, September 25th, 2020 AT 10:08 AM (Merged)
Tiny
KAREN3LAWN
  • MEMBER
  • 3 POSTS
  • 1999 SATURN SL2
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 19,200 MILES
Have misfire on #2 cylinder. Replaced spark plugs, wires, fuel injector and ignition coil. Ran better after changing out ignition coil. Anything else we can try?
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Friday, September 25th, 2020 AT 10:08 AM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
I would do a compression test on all cyls that's all u have left bedsides the ignition module computer and wiring to the ignition module that u hbent replaced. Do a compression test and let me know what the readings are.
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Friday, September 25th, 2020 AT 10:08 AM (Merged)

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