Misfire cylinder three and code p0303

2002 CHEVROLET S-10
136,000 MILES • 4.3L • 6 CYL • 4WD • MANUAL
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JCANIZZO8
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Changed plugs,cap and rotor and new distributor. Truck starts but still has miss in cylinder three. Coil changed,no change in misfire. Lean code p0303 still persists. Pulled number 3 spark plug wire off distributor, no change in engine. I popped the fuel rail and got good fuel pressure. Engine starts fine and has no power,just a misfire that I cannot find source of. No vacuum leaks.like I said,pull number 3 wire and no change in engine. it is not getting spark only on that cylinder. Is it cam position or crank position sensor, PCM?
Dec 29, 2019 at 10:44 AM
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ASEMASTER6371
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Good afternoon,

Did you check the compression on that cylinder? I would start there.

https://www.2carpros.com/articles/how-to-test-engine-compression

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

Roy
Dec 29, 2019 at 11:44 AM
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JCANIZZO8
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Yes,is at 75 psi.
Dec 29, 2019 at 4:46 PM
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ASEMASTER6371
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Okay. That is the issue. You need at least 140 to 160. That is why you have the misfire.

Roy
Dec 29, 2019 at 5:00 PM
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JCANIZZO8
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Thanks.
Dec 29, 2019 at 7:44 PM
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ASEMASTER6371
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You are welcome.

Always glad to help.

Roy
Dec 30, 2019 at 4:46 AM