1997 GMC Sonoma 1997 GMC Sonoma P0147/P0300

Tiny
G.I.E.
  • MEMBER
  • 1997 GMC SONOMA
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 155,000 MILES
I have a 1997 GMC Sonoma and I Have the following codes popup within the last month
P0147 o2 sensor
P0300 random misfire

I have purchased new wires, plugs, o2 sensor, cap, rotor and fuel filter. I'm going to replace these within the next week. I'm also going to check leaks in the vacuum system as well.

Anyone has an idea with the combination of these 2 codes? A guy on another forum told me he had the same problem and replaced the o2 sensor and it was gone.

Any other suggestions are greatly appreciated
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Wednesday, May 28th, 2008 AT 8:05 PM

6 Replies

Tiny
MASTERTECHTIM
  • MEMBER
Unfortunately I think your going to have a problem with the fuel pressure regulator leaking fuel causing the misfire and rich code from the o2 but you could get a lucky break. Let us know what happens after replacing your parts and look closely at the spark plugs on the passengers side for signs of fuel soaked. If they are then its a leaking regulator.
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Wednesday, May 28th, 2008 AT 8:12 PM
Tiny
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Tim, thanks for the quick reply.
I failed to mention I have replaced the catalytic converter with a direct fit one. I might have handled the o2 sensor too rough, the one that is connected to the converter. Downstream is the correct term I believe.

I don't have two left hands but any tips replacing these items that I mentioned?
I think the only hard part is to replace the plugs since they are not located where I can reach them easy. Any suggested special tools?
What about the fuel filter. Is it necessary to releive pressure first?

Thanks

Ron
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Wednesday, May 28th, 2008 AT 8:18 PM
Tiny
MASTERTECHTIM
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You dont have to relieve fuel pressure, just loosen nut slowly, fuel will leak out. When replacing the plugs do it through the wheel well with the front tires off, it will be the easiest and the hardest plug is the middle one on the drivers side and I find that a spark plug socket with a swivel built into it works just fine. Let us know how you make out
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Wednesday, May 28th, 2008 AT 8:23 PM
Tiny
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Thanks Tim, I happen to have one of those swivel socketwrenches.I believe santa brought we one of those a few years back :-)

If it is the fuel pressure regulator would the plugs be wet on the outside or inside, or would the wires be wet also?

Thanks.

Ron
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Wednesday, May 28th, 2008 AT 8:31 PM
Tiny
MASTERTECHTIM
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On the inside.
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Wednesday, May 28th, 2008 AT 8:39 PM
Tiny
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Tim.

I'm working on the car and all the plugs where dry. However there were 2 sparkplugs(the middle ones on both sides that could unscrew with my hands!
I think this might have been the problem right there.

I'm still going to replace the plugs, wires, cap and rotor while I'm on it. Will keep you updated

Ron
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Friday, May 30th, 2008 AT 1:31 PM

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