I have a 2004 Chevy Silverado Z71, 120k. When I purchased this truck it was bone stock. After about a month I bought a K&N Cold Air intake. After doing this my check engine light has been coming on. At first it would come on and then go off randomly during the day. I go to get the code ran it says Mas air flow and that bank 1 & 2 are running to rich. Thanks for any advice.

 

Is it an oiled filter? If so, it was probably over-oiled and got on the MAF.

You can find MAF cleaner at any autoparts store, just be very careful not to damage it.

 

Actually no, there was no oil supplied and it probably needs some. I have only had it on for about 2 weeks. Anything else?

 

the oil in your k&n is setting the code. oil has gotten on the maf. not sure on the fix...

 

Buy a can of MAF cleaner, use at least half the can of it and spray the living hell out of the MAF sensor. Make sure you get everything. Sometimes it can take a whole can but be patient and do not touch the little wires in there. First time I cleaned my K&N I had to use an entire can of the stuff to get all the oil and dirt off of the MAF.