rough idle

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dferg
Posts: 1
Joined: Mon Dec 21, 2015 11:28 pm

random miss fire

Unread post by dferg » Mon Dec 21, 2015 11:36 pm

1996 gmc sierra 1500 sle 5.7 keeps throwing code p0300 have replaced plugs , wires , distributor , cap , rotor , coil, truck starts fine then dies at idle .


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carriedi
Posts: 2266
Joined: Wed Apr 10, 2013 12:42 pm
Location: Oregon

Re: random miss fire

Unread post by carriedi » Tue Dec 22, 2015 12:27 am

three very common things that can cause a P0300 are:
1. cam retard - check with a scanner (spec is 0 +or- 2)
2. vacuum leak from intake (could be internal leak into crankcase)
3. fuel injector bad or dirty, fuel pressure, fuel regulator, fuel supply leak in intake (check fuel pressure 60-66psi), (do an injector cleaning service), (check for raw fuel in intake)
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erniejackson7

rough idle

Unread post by erniejackson7 » Tue Aug 02, 2016 2:22 pm

rough idle after changing all plugs and ignition packs, no reading from the under dash scanner,188900 miles

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carriedi
Posts: 2266
Joined: Wed Apr 10, 2013 12:42 pm
Location: Oregon

Re: rough idle

Unread post by carriedi » Tue Aug 02, 2016 10:46 pm

If you scanner won't work when you plug it in to the dara link connector check to see if you have battery power to pin 16. If there isn't battery voltage on pin 16 check for a blown fuse.
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