Question about 1999 Chevrolet Silverado 1500

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Has a 6.0 L with bad misfire under a load and is

99 chevy silverado 2500 4x4
Has a 6.0 L with bad misfire under a load and is not setting a code.
San tool is showing up to 175 misfires per cycle. sometimes it would show number 1 misfire in the data part of the scan tool, still not setting a code even after more than 2 different cold to warm trips. I swapped the #1 coil, plug and wire with the #3 coil, plug and wire. It still showed #1 as misfiring
sometimes but mostly would show the total misfires. I cleaned the mas air flow sensor, and no change. I did a injector balance test and all injectors tested the same. I checked for a vacuum leak with smoke checker machine, no leaks. I don't understand why it won't set a misfire code. Help thanks, Brad

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Hi Brad,
I ran into the same problem your going thru,
swapped cylinder plug and wire ,and the scan kep telling me it was still seeing the problem on the same cylinder,
smoked it too,nothing made sense!
Until i took the whole fuel rail off carefully not to let the fuel run out all over the engine,Had a white rag folded up and handy,tilted the rail assembly and left the fuel run on the cloth,OMG! the rust that came out of there,
I pulled every injector out of the rail,cleaned the inside of the rail with air pressure and carb cleaner.
Its when I was checking the injectors that I found the culprit,the rust pieces had made it thru the injector but were trapped in the screen of the injector!
I hope this cures your.

Posted on Dec 11, 2009

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Posted on Jan 02, 2017

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