GMC Troubleshooting Questions? Ask a Mechanic for Answers
Hello, I am Randall, Have you had the codes scanned yet? also, have you done anything to try and fix this problem?
I see you added to the description, let me review this
I do not have any information on the 3500 codes, I will opt out
Hi there, I am Cam. Sorry for the delay. Let me pull up those codes.
The P03500 and beyond codes are phantom codes generated by your scanner. There are no codes of that type in the GM manual.for your issue, Were they misfiring all the time or just part of the time?
Ok, You verified spark on those cylinders?
I am suspecting injector issues. I have seen several of these injectors fail, and to make it worse, they are direct injectors. The test we do to verify those is to check for spark on the cylinder, Then swap plugs and coils to different cylinders and if the misfire does not move , then do a compression test, and if that is good, replace the injectors on those cylinders.
Ok, that sounds like a plan. Please bookmark this page so you can easily navigate back to it so we can continue the discussion. This is done by pressing (CTRL D on PC and CMD D on Mac). You can reply at any time for follow up information regarding this issue, even after you rate the site and I will reply.
It should take more RPM to get the pressure up. If you spray a bit of fuel in the air filter, does it fire for a moment?