Misfire/miss

Tiny
WAYERS87
  • MEMBER
  • 2006 NISSAN SENTRA
  • 2.5L
  • 4 CYL
  • FWD
  • MANUAL
  • 140,000 MILES
(qr25de) CEL is on throwing p0300 random misfire and p0304 misfire cylinder number four. At idle it runs very rough and you can hear a "putt" in the exhaust, there is no smoke or rich smell. While driving and accelerating it jumps and the CEL flashes.
All I have done so far is replaced the spark plugs. The coils that connect to the plugs look very clean and I cannot find any burned or rubbed through spots on any of the wires.
Guidance?
Saturday, March 4th, 2017 AT 11:40 AM

5 Replies

Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Try swapping the coils around to see if the misfiring cylinder migrates. Coils failing do not give any indication at times and only proprer testing of the coil can provide the correct result.
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Sunday, March 5th, 2017 AT 2:47 AM
Tiny
WAYERS87
  • MEMBER
  • 7 POSTS
I moved the coil and the misfire moved with it. Now it is still throwing the P0300 random misfire, running better but still definitely not right. I tried replacing the cam position sensor but I broke the pig tail after unclipping it, put the new sensor in and tried pushing the broken plug back on, it isn't falling off or even wiggling and seems like it would be making the necessary connection but still no change. I'm trying to locate a new pig tail to see if that is my problem before I do anything else.
What am I missing?
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Wednesday, March 8th, 2017 AT 4:41 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,142 POSTS
Hello, If the misfire moved with the coil, that coil is bad please replace it and get back to us.

Best, Ken
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Monday, March 13th, 2017 AT 11:40 AM
Tiny
WAYERS87
  • MEMBER
  • 7 POSTS
Sorry left that out in my last response, I replaced the coil and no change
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Monday, March 13th, 2017 AT 2:10 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 54,142 POSTS
Hey,

I would start by cleaning the mass air flow sensor and while you are at it check the air intake boot for leaks,

Here is a guide to help you.

https://www.2carpros.com/articles/mass-air-flow-service

and

https://www.2carpros.com/articles/replace-an-air-intake-boot

Please let us know what happens.

Best, Ken
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Monday, March 13th, 2017 AT 3:29 PM

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