getting 1399, 302 and 304, engine runs fine

 

Is the engine light lit solidly or actively flashing? The ECM's code parameters are a lot more sensitive than we are as drivers and sometimes a misfire event will be subtle enough that you won't notice it. If the light is flashing, the engine is actively misfiring. If the light is solidly lit and a misfire code is read, the misfire event isn't actively happening and the engine may in fact be running fine at that moment, but the misfire has already occurred and may happen again.