motor is a 4.8 with 114,xxx miles

well started about an hr and a half ago. started the truck up everything was normal then i turned it off and went to fixing my reverse and turn signal lights. turned the key forward (but not on) to check the reverse and they were good. and i did have the parking brake on when i put it in reverse just in case. went and turned the truck on and it was completely different. rough idle, CEL flashing. took the truck up to autozone and got those codes. ill be checking my spark plugs and wires here in a min. and this is the FIRST time its ever thrown a code before

 

The 300 is a missfire code, the 200 is injector related, voltage code.. Make sure all the plugs are good on the wires, on the coil packs..

 

yea im familiar with the codes. the spark plugs and wires are all good but im sure there well over the recommended mileage that there supposed to be changed out.

now i had the truck running and i was unplugging each injector connector starting on the drivers side and 1, 3, 5 and 7 injectors didnt effect the idle, but the 2, 4, 6 and 8 injectors really effected it. it made it worse. so idk im thinking it might be the spark plugs but then again the passenger side injectors

 

If little or no change was noticed while un-plugging 1,3,5, and 7, The problem is with those cylinders, NOT the passenger side. the fact the passenger side made a change proves those cylinders are contributing to the global cause of truck go fast.......
Check the main coil plug for the left bank.

 

ahh thanks for correcting me. it makes sense now why it didnt change the idle. ill check the main coil plug tomorrow after school when i get home