Emissions problem??

HEY I have a 95 blazer 4.3l W and I can't seem to pass the HC test for emissions. I passed it before. I've replaced the fuel injector system. Also replaced O2 sensor, spark plugs and wires. I drove it with the bad fuel injectors with the new spark plugs for about a month. Could my spark plugs wet bad. It had to have been something I did. Please help