backfires

1999 CHEVROLET BLAZER
100,000 MILES • 4.3L • 6 CYL • 2WD • AUTOMATIC
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STEVE BOOK
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  • 4 POSTS
truck backfires the PCV sometimes on starting, but
runs perfectly after resetting PCV cap.
Nov 18, 2016 at 10:48 AM
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JIS001
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  • 3,412 POSTS
Do you have the correct PCV valve installed? Also have you tried scanning for codes? I would use a more advance scanner for that rather then the quick small ones.
Nov 18, 2016 at 11:01 AM
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STEVE BOOK
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  • 4 POSTS
I have ordered the PCV valve. The only code that shows up is a knock sensor.
Nov 21, 2016 at 7:36 AM
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JIS001
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Okay, replace the valve and reset the light and let us know if that fixed the problem or if the code returns.
Nov 21, 2016 at 9:18 AM
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STEVE BOOK
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replaced the valve, the only code is a knock sensor, an if still backfired.
Nov 25, 2016 at 7:38 AM
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STRAILER
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Hey Steve,

I backfire could be caused by an leaking intake valve, here is a guide that will explain all reasons for a backfire.

https://www.2carpros.com/articles/engine-backfires-while-running

Please run some tests and get back to us so we can continue helping you.

Best, Ken
Nov 26, 2016 at 7:14 PM
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STEVE BOOK
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  • 4 POSTS
does anyone know where the gulp valve is located on 1999 blazer?
Nov 30, 2016 at 12:40 PM
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STRAILER
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If your engine has one it will be near the exhaust manifold on either side.
Nov 30, 2016 at 8:28 PM