Random multiple miss fire P0300

Tiny
MIKEDEROUIN88
  • MEMBER
  • 2006 CHEVROLET EQUINOX
  • 3.4L
  • V6
  • FWD
  • AUTOMATIC
  • 166,000 MILES
My customer had a valve drop on his 2006 Equinox. He asked me to replace his motor with a used one from a reliable used motor and transmission dealer.

After installing the used motor there is a P0300 trouble code. I double checked all my work. I replaced the spark plugs with new AC Delco Iridium OE plugs. The coil pack and plug wires are off of the original motor which had no problems prior.

Can you please give me the cylinder identification and possibly give me a few pointers on where to look next.
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Monday, November 25th, 2013 AT 9:44 PM

6 Replies

Tiny
HMAC300
  • EXPERT
If you dont' have experience with this have a pro look at it. Misfires are extremely hard to diagnose. If you have a pro style scanner look at your reading and see if anything is out of whack. Also check for vacuum leaks, hoses off etc.
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Tuesday, November 26th, 2013 AT 6:17 AM
Tiny
MIKEDEROUIN88
  • MEMBER
I am a ASE certified and have a fairly good scanner. Im just wondering if there may be a common problem with this model vehicle. Since it is a used motor its hard to find a starting point. I was leaning towards a fuel injection problem but I have not checked for vaccume leaks so I will start there. That's very helpfu. Thanks for the pointer and if theres any way you can get me the cylinder identification so I can double check my wires that would be great. I assumed it was just standard General Motors. With 2 4 6 on the front and 1 3 5 on the back.
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Tuesday, November 26th, 2013 AT 9:49 AM
Tiny
HMAC300
  • EXPERT
I dont' think you get a misfire code with cwires crossed but hell you never know. Here ya go
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Tuesday, November 26th, 2013 AT 9:53 AM
Tiny
HMAC300
  • EXPERT
Another pic with firing order
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Tuesday, November 26th, 2013 AT 9:54 AM
Tiny
MIKEDEROUIN88
  • MEMBER
I have seen a P0300 caused by crossed wires but only if its 2 or more cylinders and the was they make cars now I doubt it would even start if that was the case. But I have been fooled before. This motor is such a simple designe there's not a lot to it and being that its a used motor that we know nothing about I want to be extra sure everything was installed perfect before I start pointing fingers at the used motor. This is exactly why I try to avoid installing used parts. But with todays economy you have to take whatever work you can get. I am going to put the smoke machine on it tomorrow and check for vaccume leakes. I will let you know.
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Tuesday, November 26th, 2013 AT 5:12 PM
Tiny
HMAC300
  • EXPERT
If you have mode 6 on your machine run that and it might single it out prior to doing smoke test.
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Wednesday, November 27th, 2013 AT 6:14 AM

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