Fault code P0300 & P0303

[psychochops78]

Good morning all. I'm new to this forum and I'm looking for some help if possible. My check engine light is on and when I hook the code reader up it comes back with P0300 and P0303. P0300 isn't always shown but P0303 is consistant. I've changed spark plugs and put in accel super coils on it. Getting ready to pull fuel injectors and check them as well. Hoping this isn't a compression issue. But if it was a low compression issue, would't it run like crap all the time? Sometimes it runs like a bat out of hell. Other times it runs like poo. When it is acting up, it's usually in 1st or 2nd gear when I'm in the low RPM range and I get on it. It bogs down and shudders pretty bad. Other times is when I'm in 4th or 5th in the 3000-4000 RPM range and start to accelerate, I feel it hesitate and that's when the check engine light starts to flash. Does anyone have any thoughts on this or can point me in the right direction? It's been a great little car and I don't want to let it go but then again it does have 275000+ miles on it and I'm the original owner of it. Any help would be greatly appreciated.