Hello, I have a 2004 Silverado with the 4.3 V6. Over the last few months it’s started to have an issue where it would be difficult to get started if it had sat for longer than a day. But if I started it every morning it would run and drive perfectly.



It had already needed scheduled maintainance, so I have so far replaced the spark plugs, wires, cap & rotor, fuel pump and sending unit, and brand new gas tank (old one had cracked).



About a week ago it finally died to where it’s not starting at all anymore and just turns over. The only code that came up was a P0300 general misfire. Looking at the live data, the only things that are reading as abnormal are the “Injector PWM bank 1 average” and “Injector PWM bank 2 average” which are both reading high. It says the normal range is between 0-20 ms, and both banks are showing a little over 30 ms.



I suspected the injectors were clogged, resulting in the ECU turning them on longer to compensate. So I proceeded to remove them and bench clean each injector with brake cleaner and tapping the pins to 12V to pulse them, and each one was definitely flowing when I reinstalled them. I also cleaned out the spider module that feeds them as best I can as well. But after putting everything back together it still isn’t starting. Even spraying starting fluid into the throttle body isn’t getting it to fire up even if only for a second. I am beyond stumped at this point.



I have also so far done a cylinder compression test which is reading around 125 psi. I’ve verified there is 12 volts going to the coil as well as hooking up an in-line spark tester which lights up as it’s turning over.



Has anyone else had a similar issue? Where the injector pulse width is reading high for both banks? Please ant and all suggestions are welcome! I have pics and screenshots of all the live data if that helps. It’s an Autel scanner so I am really surprised that I’m still not able to pinpoint what’s causing this…

 

Did you get anything figured out. Same here.