Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
I am sorry your having this problem
which cylinders are the codes saying are misfiring or which cylinders show a misfire when the check engine light is flashing if you have access to a scan tool to see live current or history misfire data ?
usually when all will show a misfire it is usually an issue with something that is involved with all the cylinders
the best action to take is to be sure there are NO vacuum leaks at the lower intake manifold gasket where it meets the heads and be sure any grounds on the front of the cylinder heads and or the ground on the back passenger side of the intake manifold are clean and tight
if those all check out see if the fuel pressure is reading 55 - 62 key ON engine off
if the pressure is below that or drops to 0 withing a second or very close to 0 then run the truck for a few minutes and shut it off then remove the vacuum line at the fuel pressure regulator on the drivers side fuel rail if you see ANY fuel leaking out of the port on it that the vacuum line connects to it then replace the regulator then re test the pressure if the pressure still is low or drops to 0 within a second replace the fuel pump
if the fuel pressure tests good or still does this after the fuel pressure is corrected then replace the crank sensor behind the starter in the engine block
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