Need help with fault code PO300

I have a 98 avenger 2.5 v6. I have a fault code PO300,that means "multiple misfire.Has any one incountered this problem.The car idles erractly and doesn't have any power going up hills. I have changed the plugs,wires,cap and rotor. Any help would help thanks:shakehead

I have a 98 avenger 2.5 v6. I have a fault code PO300,that means "multiple misfire.Has any one incountered this problem.The car idles erractly and doesn't have any power going up hills. I have changed the plugs,wires,cap and rotor. Any help would help thanks:shakehead

try fuel filter and pump

Don't buy cheap gas. My avenger couldent get up hills in penn. untill I topped up with premium. American gas sucks.
Also, did you make sure to buy the parts from the dealer? Aftermarket plugs don't work in Chryslers. Chech the spark output and make sure you have even spark at least 40 000 volts. Fuel pressure may be a problem, but if you have tried these, check to make sure the timing belt hasn't skipped a tooth.