P1399 98 civic lx
 

got this p1399 code. it says misfire any cylinder. Could someone who has encountered this problem before tell me how to trouble shoot and find the reason for this code coming up. Also, could a misfire be causing my car emit high emissions at 25 mph and up. It wont pass the smog test and the guy at the smog place put the scanner after it failed and showed me the code- p1399 - misfire any cylinder.
THANKS A BUNCH.