Crank sensor

1997 CHEVROLET SILVERADO
150,000 MILES • 7.4L • V8 • 4WD • AUTOMATIC
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TUCKER ONE
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Was starting hard, found the crank sensor was loose. tightened and ran good until hot. Misfires and runs terrible, will not even make a hill. the more gas you give the worse it runs. Sometimes if you let up a little bit it will smooth out and pick up speed until you move the gas pedal then it falls on its face. Like it is running on four cylinders.
Jan 23, 2017 at 1:32 PM
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STEVE W.
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Change out the crank sensor. It may have been damaged while loose. Check the wiring as well. The symptoms you give sound timing related.
Jan 23, 2017 at 1:57 PM
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TUCKER ONE
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I think that you are right about it being timing related. I just do not know why it will come out of it at certain speeds and run really good when engine is cold. Any ideas on that?
Jan 23, 2017 at 2:15 PM
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STEVE W.
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  • 15,113 POSTS
Typical crank sensor issue is being temperature sensitive. If you have access to a scan tool you can actually look at the signal and see what it is telling the ECM to do with regard to timing and injector pulse.
Jan 23, 2017 at 5:31 PM