I put a K&N 57-7000 filter on my 996 then about couple of miles my check engine lights on.I scan it i got the 1128 code,i clean the MAF sensor with CRC cleaner then i reset the code,the check engine came off for a while now it came back again.ANY IDEA

 

You will get this fault if there are any air leaks where the MAF mounts, or where the intake tube mounts to the throttle body. It's also not unheard of that the MAF was failing to begin with, and the extra air flow of the K&N intake is bringing that out (especially if the old air filter was dirty and restricting air flow).