Hope y'all are well today. So, I had a reoccurring code p1174 for a couple of month. It would go off, turn on of three days, and turn off. I took it to the shop when it would come on. The light would turn off for two weeks and repeat the previous pattern. This weekend, the shop did a fuel injector change and cleaned the system and the light was off. I drove back from my mechanic and a new engine code p0304 cylinder 4 misfire shows up. Should I swap the plugs to sus out the problem? I'm a college student so, if possible, I don't want to drain my savings or move back home and be far from campus.

 

Yes, that's a easy and free diagnostic tool. Swap the plugs between 4 and 3. If you have separate coil packs, Swap them also, between cylinders 4 and 2. See if the code you get changes.

 

The P0304 is not new, you just did not see it. It is the cause of the P1174.
When were the spark plugs last replaced? If you have the correct ACDelco 41-103 plugs they are good for 100,000 miles, others are not.
If you have checked the plugs and they are good, you need to do a compression test to find out if there is a mechanical problem in cylinder #4.