Random misfiring and backfiring

2000 CHEVROLET TRAILBLAZER
259,000 MILES • 4.3L • 6 CYL • 4WD • AUTOMATIC
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JAMES K.WILSON
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The code is p0300. It began running sluggish. Then day before yesterday when I accelerated going up a hill it backfired and skipped. It has been random but steadily getting worse. I replaced the spark plug wires and removed the distributed cap and rotor and cleaned them as best I could. The screws holding the rotor were rusty indicating moisture (that was this morning). Last night I checked for sparks in the dark. I found very small sparks around a loose bolt that holds a hose strap down to the manifold. I tightened it this morning. I cannot see sparks but nothing else changed.
Nov 27, 2017 at 8:12 AM
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STRAILER
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It sounds like the rotor and cap are having a problem. can I ask what brand spark plugs and wires you installed ?

This guide can help as well.

https://www.2carpros.com/articles/engine-misfires-or-runs-rough

Cheers, Ken
Nov 28, 2017 at 1:28 PM
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JAMES K.WILSON
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Thanks, you are exactly right. I replaced them this morning before I saw your post and it's running fine now.I do have a little play in my rotor so I'll replace the distributor soon. Thanks for your speedy and accurate reply.
Nov 28, 2017 at 3:14 PM
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STRAILER
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Good to hear, please use 2CarPros anytime we are here to help.

Cheers, Ken
Nov 29, 2017 at 10:54 AM