Ok I have always had a paper filter, but two days ago I put in a k&n filter that I got from ebay. The next day my engine light came so I got it scanned and got two codes for bank 1 and bank 2 being too lean. The code will sometimes go away and then come back. Was this caused by putting in the k&n filter?

 

highly doubtful, check for intake leaks from when you reinstalled everything

 

I didn't take anything off I just unclipped the lid.

 

I think what txhorns281 means is You have 2000 t/a with ls6 intake which is not stock so Regardless when or who installed the intake the bolts can come loose. I have had my intake off a few times. I have always had to recheck them. and if you are getting those two codes I would say check for the intake for leaks too. Got those codes b4 one was due to LT's coming loose and the other was intake bolts not tight enough. Make a 44"lbs pass on them first then to 89"lbs. You will need to look at the diagram on www.ls1howto.com for the sequence of tighting the bolts. and a 10mm socket. Hope this helps ya.

 

The only K&N problem that can happen is the oil from the filter getting on the MAF and making it not read properly.

Go to the local radio shack, buy "residue free QD electronics cleaner."

Spray that on your maf wires. DO NOT touch the wires. Hopefully this will solve your problem.

 

what he said

 

This is good advice. Ive used non chlorinated brake cleaner as well.

 

Another thing that works very well is use rubbing alcohol and a Q-Tip.

There are 3 sensors on the MAF. Take it apart and gently clean each one with the soaked Q-Tip. I "fixed" many like this...

The MAF sensors from the 1980's and some newer Ford MAF sensors are the ones you can't touch...

 

If anything is "leaning" you out in your setup I would think the SLP 85mm Maf would be the culprit. In addition to the H/C swap I put on a ls6 intake, BBK 80mm Tb, SLP 85mm Maf and run a K&N filter. After recalibrating the VE table, and bringing the Maf back online initial scans with EFI Live revealed a overall lean condition. After removing the SLP added resistor and rescaling the Maf all was well. The SLP Maf by it'self leans out the factory pig rich calibration with that added resistor. More mods make the stock tune more irrelavant. I think in your case the K&N's better airflow probably was just enough to pop the code-although the other suggestions of checking the LTs / intake for loose bolts would be good to do in conjunction with rescaling the Maf.