my crx stared to act normal for a few days by running fine and strong.. after i made a 90 mile journey it runs worse than before.. i went for about an hour at 60 mph and nothing happened it ran fine.. then my check engine light came on.. i was like ****. i turned my car off and popped the clutch and it started.. check engine light was off.. then exactly one miniute later.. i did this turning off and on for almost 20 min straight.. i noticed little by little my air fuel ratio would be leaning out constantly but at a slow pace.. i have an apexi afc.. the old style with the dials and ****.. i keep them on 0 always.. how do i check to see if in throwing a code on my ecu?.. that could be a cause.. right?.. once again anyhelp would be great! thanks alot!