'97 avenger 6 cyl engine light is on. The engine momentarily lost some power a few times while local driving. Now the car is running fine and made a 150 mile highway trip with no problem. We had the codes read at Autozone and there are 3:

P0304
P0134
P0300

Codes show possible cylinder misfire, vacuum leak, injector fault, hig/low fuel pressure, ignition system fault, spark plugs, wires, coil. Everything except coil was replaced 6 months ago.

Any suggestions as to whether we should be concerned now that the engine is running well are appreciated.