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Ignition issue.

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Old Jul 14, 2015 | 12:58 PM
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Default Ignition issue.

72, 454 HEI and MSD box.
Car was unstable at idle but ran fine otherwise.
Red that pluggap should be 0,045 with HEI, had 0,035 previously.
Adjusted to 0,045 and the car ran like crap when it got hot, stumbles and misfires.
Went back to 0,035 and it still runs like crap...
Could it be that plugs or coil has been damaged.
Strange thing is, when it is Cold it runs perfect.
Please someone, give me a solution!
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Old Jul 14, 2015 | 03:07 PM
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You have a vacuum leak. When it's cold the choke is closed and masking the problem.
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Old Jul 14, 2015 | 03:11 PM
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What is the quality of your spark plug wires? Big blocks have always been sensitive to spark plug wire quality.
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Old Jul 14, 2015 | 04:10 PM
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Originally Posted by dochorsepower
What is the quality of your spark plug wires? Big blocks have always been sensitive to spark plug wire quality.
It ran just fine Before i started to fiddle with sparkplug gap...
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Old Jul 14, 2015 | 04:13 PM
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Originally Posted by dochorsepower
What is the quality of your spark plug wires? Big blocks have always been sensitive to spark plug wire quality.
MSD street fire wire, ran god Before plug adjustment.
But i have been thinking of that and the coil.
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Old Jul 14, 2015 | 04:40 PM
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could you have broken the connection in the spark plug boot by pulling on them when changing the plugs? Do you have an ohm meter to test them?
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Old Jul 14, 2015 | 04:48 PM
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Originally Posted by MelWff
could you have broken the connection in the spark plug boot by pulling on them when changing the plugs? Do you have an ohm meter to test them?
Checked all plugs before reinstalled them, did not ohm them.
Did ohm all Cables, could not detect any issus.
Thing is, why does it run god when cold??
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Old Jul 15, 2015 | 05:46 PM
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leaning out after choke is off. probably a vacuum leak.
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Old Jul 16, 2015 | 12:17 PM
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Pulled all plugs again and found one that had a small almost not visible crack.
I am so relieved!
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