My 98 GMC Jimmy won't start.?

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Vaden

New member
Okay, when I turn the key over it's trying to start but won't. I have' changed the computer, spark plugs and wires, distributor cap and button. And I have the check engine light P0300, maybe I didn't put the wires and plugs on tight? but I know the button is lined up right and all the wires are in the right orders. And after the new computer was put in the security system has been cleared.
 
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bandit_60

Member
PO300 is a cylinder misfire. is the fire to the plugs good and strong? if you have a weak spark like yellow then it could be the coil weak. check the spark at the plugs while someone cranks the engine. what about the module in the distributor, did you change it?
 
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straightlshooter

New member
Why did you replace the PCM? Did you have it flashed?
P0300 is a random cylinder misfire. Usually not a ignition wiring problem, it'll be something that affects all cylinders at once. Check for vacuum leak, unplugged hose, low fuel pressure, etc.
Take it to a qualified mechanic ASAP
 
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