I haven't found a thread with my issue so I'm sorry if I missed one.
I have a 2005 Silverado 1500 LT 2WD
I have tested the coil packs, replaced wires and plugs but still get this DTC. I had a cold air intake on it, but went back to stock to see if it was the issue. I believe I got hold of some old gas and I added a bottle of techron and topped the tank with non ethanol gas but it still pops up at 2K rpms. I have cleaned the MAF and throttle body ( not removing the body though). I cleaned all connections with contact cleaner as well as rechecked the plug connections. The plugs I removed had the smell of varnish on them so I figured it was bad gas. I'm guessing I'll have to let it run it's course. Next chance I get, I'll check the fuel filter to see if it could be attributing to the problem. It only has a slight vibration at idle and the code pops when accelerating to 1500-200 rpm.
UPDATE: After removing and clearing injector #7 and running a cleaner through all of the injectors it is running smoothly

 

You really need a decent OBDII coder reader/live data scanner that will let you monitor and store data for cylinder misfire counts. That way you can see if there is one or more cylinders misfiring occasionally misfiring, or if there is a single cylinder misfiring below the set a code threshold.

Also, check the fuel pressure. A weak fuel pump can also cause a P0300. I'm sort of leaning towards this at the moment because you say the P0300 pops up when the engine is running at 2000 rpms.

Do not be surprised if you cannot find a fuel filter because most 2005 Silverado's have the fuel filter incorporated into the fuel pump assembly if I recall correctly.

Good Luck!

 

Yeah, think Chevy went to the filter-in-pump in 2002 to 2003. Sure glad my 98 K-1500 is still on the frame. My 15' Malibu has that as well as a transmission oil filter stuck on the to thr of my automatic transmission, inside where one cannot change it.. At least I can change the A/T fluid as there in a drain plug at the bottom and you refill with 4.5 quarts of Dexron VI at the vent hole on the top of the transmission. "Sealed for life is not true" is incorrect, IMO

 

It was #7 being clogged, I cleared it and all is well now

 

Thanks for the update!