So I have been getting this P0304 misfire code for about 6 months now. I have changed the spark plugs twice, changed all the coil pack, changed the vacuum pump, done a compression check, done a pressure test on the fuel injectors, and done a vacuum leak test and till keep getting the code. The crazy thing is the check engine light comes on and the engine idles rough and runs rough for about 1.5-2 weeks and then the light goes out and idles and runs smooth. Then the light comes back on again and starts all over again. I have also gone as far as replacing the ECM. Any suggestions or advice would be great.
