I just got this OBD2 engine code reader from ebay today so i checked my car even when the CEL is not on.
I got 3 codes from it "misfire deected" "cyl.3 misfiring recognised" and "Bank 1, Mixture adaption (add)system too lean"
Are they problems from before and saved in ECU?? or actually I have these problems??
need some advise....

 

they are whats called soft errors and not considered a threat to the ECU or performance of the engine, if they happen more than once or twice then they throw the CEL on so just clear them if your code reader allows

 

clear them and see if they come back after driving some.

 

I cleared the codes lastnite and this morning when I check the engine code again the same code pops up again withuot CEL on
"misfire detected" "cyl.3 misfiring recognised" and "Bank 1, Mixture adaption (add)system too lean"
After I tried to swap the cyl2 and 3 coilpack and plug cylinder 3 is still misfiring, and I check the gap on my new spark plug but all of them are correct.
Could it be ICM??? or I need to clean the injector??Just what is causing cylinder 3 misfire....BUt the CEL is not on....should I be worry about this???

Do you think misfiring is causing the engine run lean??? or is it some other reason like airbox mod??

need some advise...thankx

 

One more question...does 99.5 A4 has ICM?? I didn't see anythin' on top of airbox except some sensors and wires......