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Gary, Chevy Technician
Category: Chevy
Satisfied Customers: 17035
Experience:  15 years GM master tech
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I own a 2001gmc 2500 he 6.0 liter. I have been experiencing

Customer Question

Hello I own a 2001gmc 2500 he 6.0 liter. I have been experiencing a flashing check engine light for a while now. I replaced the fuel filter last week along with the battery. Then scanned and replaced cylinder 1 and four coil misfire code this morning. When I bring engine up to 2000 rpm the check engine light flashes then stops after 45 seconds wtf
Submitted: 1 year ago.
Category: Chevy
Customer: replied 1 year ago.
The motor has 210000 miles on it and the fuel pump had been done over 120000 miles ago. Maybe pump is not working properly? Pressure test because it does not start on the first try it starts on the third
Expert:  Gary replied 1 year ago.

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 ?

Customer: replied 1 year ago.
At idle cylinders 1 and 4 and I replaced coils. At 2000 rpm the light flashes and all cylinders misfire
Expert:  Gary replied 1 year ago.

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

if you have any questions please ask as i do not get credit for my work until you rate us here at Justanswer !