brutus25

I have an 05 Silverado Crew Cab z71, 5.3 and had a water pump go bad two weeks ago. It seems like the front seal gave out and dump all the antifreeze all over the engine. I replaced the pump and all was fine until Sunday morning. Went out started truck, fired right up, then it began to run rough and the check engine light started flashing. Shut the engine off, check things and restarted and no CEL now. Pulled codes and got P0200 and P0300. Any idea on what the problem might be?

mrvedit

P0200 is Injector Circuit Malfunction. P0300 is random misfire which is likely due to the injector problem.
I would carefully check the wiring and connectors to the injectors, especially the front two cylinders closest to the water pump. Either a wire got yanked during the job or a connector is filled with antifreeze. If you have an air compressor, try blowing out the connectors, unclipping each one.
Hey, just some ideas.

brutus25

mrvedit thanks for the reply. I'm planning on doing the exact same thing you suggested tomorrow and hopefully that will fix it. I'll be sure to let you know. Again thanks.

brutus25

I removed all connectors on the injectors and coils, used air compressor blew them out and reinstalled. I didn't find anything with them. Added Lucas fuel injector cleaner and filled tank. Truck is running like a champ now. I suspect maybe an injector may have been sticking.

mrvedit

Thank you for the update. Glad you got it running, even if unsure what helped.