Question about 1999 GMC Yukon

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Po300 multiple random misfire

I'm lost! code was setting prior to new engine however, engine 5.7 LTRE replaced as well as, fuel rail and injectors, distributer, cap and rotor, o.e.m plugs and wires, coil, fuel pump and fuel filter, crank sensor. all ignition new except ignition control module. it is misfire under hard acceleration, towing and climbing and cruise at 1800 rpms or higher on cylinders 2 & 3. most of these items were replaced with the intent to make a used "NICE" vehicle new again now I'm perplexed and am giving up. 2&3 cylinders are the same pin on the crank sensor..........HELP! thanks

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  • GMC Master
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I can recommend you to RUN the scanner/computer for easy diagnostic and fix it. The electronic vehicle is complicated you have faulty the PCM or BCM.etc.
see the diagram attached.
God bless youpo300 multiple random misfire - c866fa48-e955-4fe4-9791-3cd538919029.jpg

Posted on Jul 10, 2013

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Posted on Jan 02, 2017

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SOURCE: HELP! I have a 95 gmc 4x4... sank it underwater.

the starter could be too close to the flywheel. try adding a couple of starter shims. it also could be drawing to many amps from internal corrosion from water intrusion.

Posted on May 07, 2009

bryant329
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SOURCE: 2000 GMC Sierra 4.3L no spark at the plugs...HELP!

no codes. most direct components changed.
computer. take it out or have the truck towed to the shop/dealer to test the computer.

Posted on Sep 25, 2008

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SOURCE: 2005 Jimmy 4X4, 4.3L, P300 multiple misfire. Have

Try some injector cleaner in the fuel--there might be some water in the fuel also. Check the air cleaner.

Posted on Aug 01, 2009

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SOURCE: 98 Chevy Vortec 5.7 NO SPARK

your ecm or engine control modual, usually located behinde the glove box.. it fontroles the coil and distrubator funonctions

Posted on Aug 14, 2009

  • 1608 Answers

SOURCE: vehicle misfire... diagnostic code is 1351

Code 1351 is for the ignition control module.Ignition control circuit high.This module is on the same bracket as the coil.Before you buy a new one.Try a salvage yard and get a used one.

Posted on Nov 19, 2009

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It reads codes po300 po300 po522 but it runs perfect sometimes I need to press fuel pedal to start?


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I have a po 300 engine code random cylinder misfire i change cap rotor and wires problem still exists


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