1989 nissian pickup, Z24I 4 CYL, 133K miles, failed emissions  test
today, please any suggestions.
HIGH Hydrocarbons at IDLE (765 rpm) HC = 320  LIMIT = 200 FAILED
results:
HIGH RPM                                  
HC   =  56           LIMIT 200          
CO   =  0.60        LIMIT 1.20          
CO2 = 14.8                                  
O2   = 0.75                                

LOW RPM
HC  = 320   LIMIT 200    FAILED
CO  = 0.78  LIMIT  1.2
CO2 = 15.0
O2  = 0.22
haven’t driven in awhile. today changed plugs, air filter, pcv filter
and replaced muffler. truck runs great, no problems at all. good
power, idles
fine  etc.
thank you guys