Rough start, runs smooth. 100+K miles on a 99 Siverado. Cause?

Greetings all. Seems like there are some very experienced mechanics, techs, motorheads, etc. in this group. You guys have no doubt seen it all, or at least most of it in your day.

I would like some advice. I have a stock 99 Silverado 1500 in LS trim with the 5.3L in her. Auto tranny, A/C, power stuff, tow package. She runs fine. Gas mileage has never varied. I put in new spark plugs at around 75K. Thing is, she gets off to a rough start during the ignition process. When I start it after it sits for anylength of time over about an hour, it runs rough for about the first 10 seconds or so after starting, then it settles down.

I'm looking for possible suggestions as to the cause. I humbly draw upon the supreme intelligence of the collective group as to the possible sources of such a condition.

Air filter, fuel filter and (as I mentioned earlier) spark plugs are recent. Oh yeah, I keep the oil and filter changed every 3K - 4K miles.

All you Chevy Gods out there, please don't let me down!!! Thanks

Reply to
Don in Austin Texas
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Try measuring the resistance of the spark plug wires.You may have developed a break in the wire causing a miss fire or cross over. Good luck.

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Jon Waring

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Adair Winter

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Jeremy Bomkamp

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