lights flickering and surging

1999 CHEVROLET TAHOE
170,000 MILES • 5.7L • V8 • 4WD • AUTOMATIC
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JESSE203
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starts and idles fine and runs good until it gets up to operating temperature then it starts surging and misfiring the speedometer goes crazy. if you stomp on the gas pedal it runs good or let it get back down to idle it runs good. also, the headlights and interior lights flicker when its running.
Mar 15, 2018 at 9:17 PM
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MHPAUTOS
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may be a voltage stability problem, have you had the battery tested, checked alternator out put and checked all main electrical terminals are clean and tight?
Mar 15, 2018 at 11:47 PM
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HARRY P
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To me it definitely sounds like a voltage problem. GM's are bad about voltage regulators that quit working correctly when warmed up. And their regulators are built in to the alternator, meaning you have to either rebuild or replace the alternator. Given its age, I would replace it rather than rebuild. Definitely have the alternator and battery tested and see what is what. AutoZone, Advance Auto, and O'Reilly all test batteries and alternators for free and it only takes about five minutes.

And as suggested above, make sure that the terminals are super clean and tight enough that you simply cannot move the terminals by hand.
Mar 16, 2018 at 4:03 AM
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MHPAUTOS
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Thanks for the backup Harry, sometimes working from the other side of the world you do not get to know all the known problems of your cars that we do not see, always good to get some local know how on board. Cheers, Mark in Australia.
Mar 16, 2018 at 4:53 AM
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JESSE203
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Thank you all for the help. I fixed it today one of the wires running to the crankshaft sensor was starting to break apart.
Mar 16, 2018 at 6:26 PM
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HARRY P
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Ah must have been the lead wire. Either way, we are glad you got it solved. Please feel free to come back any time.
Mar 16, 2018 at 6:57 PM
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