No spark on one cylinder when car is warm

1998 HYUNDAI ACCENT
100,000 MILES • 1.3L • 4 CYL • 2WD • MANUAL
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ANTHONY DE BARROS
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My car starts fine and runs fine until the engine is hot.there is no spark on one of the plugs. I have changed the coil, leads, plugs, rotor and distributor cap and pick up unit in the distributor. I do not see an electronic unit anywhere.
Jun 17, 2018 at 11:42 AM
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KHLOW2008
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Hi,

Have you confirmed that sparks is missing or just that the cylinder is misfiring? An engine equipped with a distributor is not likely to have missing sparks on one particular cylinder only after heating up.
If it is misfiring at operating temperature, it could be due to issues related to the compression. Engine compression are affected by valves clearances, either too much or insufficient clearance.
Try testing the engine compression and check the valve clearances too.
Jun 18, 2018 at 6:44 AM
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ANTHONY DE BARROS
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The car runs fine for twenty minutes. I then removed the lead from the one plug and the idling did not change. I then checked for spark on that lead and there was no spark. There is spark on all the other leads.
Jun 19, 2018 at 1:41 AM
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ANTHONY DE BARROS
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After letting the car idle until the fan came on it was fine. Only when I drove the car for ten minutes did it start misfiring. When I checked for spark there was no spark on the one plug lead and intermittent spark on the second lead. The other two leads had constant spark. Now I am totally confused.
Jun 19, 2018 at 4:14 AM
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KHLOW2008
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Seems like you have a fault with the distributor itself. Check the distributor shaft for excessive side play. The bearing of the center shaft could be bad resulting in the shaft moving too far away from the pickup causing the misfiring.
Jun 19, 2018 at 7:29 AM