1996 Chevy S-10 with 4.3L

Tiny
SWILSONSR
  • MEMBER
  • 1996 CHEVROLET S-10
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 125,000 MILES
I have a 1996 Chevy S-10 with a 4.3L. The truck suddenly started running rough and backfiring with a P0300 troublecode. I have replaced the sparkplugs, plug wires, rotor, distributor cap, fuel filter, and camshaft position sensor. I also checked the fuel pressure at 55 psi. The coil checks out with ohm meter. No noticable vacuum leaks. It is still running the same. Suggestions?
Wednesday, August 10th, 2011 AT 10:52 PM

10 Replies

Tiny
FIXITMR
  • MECHANIC
  • 9,990 POSTS
Backfiring out exhaust or intake? You may have an injector problem.
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Wednesday, August 10th, 2011 AT 11:40 PM
Tiny
SWILSONSR
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  • 10 POSTS
Exhaust
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Wednesday, August 10th, 2011 AT 11:48 PM
Tiny
FIXITMR
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You bought some parts but it still could be a distributor related problem. Teh gear drive or the module or the hall pickup. Or your MAF could be dirty or your coil could also be acting up or it could be your injection system. And there's always the EGR to consider and I think your vehicle has 4 OX sensors? This engine system has been a veritable headache for too many owners! But most suffer injection woes. And it's almost always dirty/sticky popits or the fuel pressure regulator.
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Thursday, August 11th, 2011 AT 3:55 AM
Tiny
SWILSONSR
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I checked the coil with an ohm meter and it was in specs, but could it still act up. The truck runs the same whether cold or warmed up. Would there not be a troublecode for the others (MAF, OX sensors, EGR, and injectors)? With respect to the distributor, what and where is the module? Is the Hall pickup also known as the crankshaft position sensor? Is there any way I can bench test these items (Module, Hall pickup, EGR, OX sensors, and injectors) myself? Where would you start looking for the cause of the problem? Should I just replace certain items?
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Thursday, August 11th, 2011 AT 2:46 PM
Tiny
FIXITMR
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What about the crank sensor? Hall is cam position. Have you pulled intake to look at spider injection? Here's a test page/site for your stuff.
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Friday, August 12th, 2011 AT 4:27 AM
Tiny
FIXITMR
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Another thing. Take a compression test! These engines have been known to blow the head gasket between cylinders causing rough running and misfire code.
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Friday, August 12th, 2011 AT 4:40 AM
Tiny
SWILSONSR
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Ok, I'm going to give it a try. Will let you know. Thank you
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Friday, August 12th, 2011 AT 1:40 PM
Tiny
SWILSONSR
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  • 10 POSTS
I replaced the spider injection and fuel pressure regulator, The truck still runs the same with a P0300 code. Compression is normal in all cylinders. What else can it be?
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Monday, August 15th, 2011 AT 10:12 PM
Tiny
SWILSONSR
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Also the code reader has "inc" for catalyst mon, Evap Syst Mo, Oxygen Sensor Mon, Oxygen Sen Htr, and EGR system mon. Even after allowing the engine to run several minutes.
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Monday, August 15th, 2011 AT 10:20 PM
Tiny
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Inc means incomplete. You didn't complete a proper diving cycle to complete tests.
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Monday, August 15th, 2011 AT 11:26 PM

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