Did I put the wrong oil on my TRD air filter?
 

I have a TRD airbox and a couple of days ago I cleaned out the filter using aFe Power's air filter restore kit with the gold oil. I selected this cleaning kit because I found a TRD high air filter cleaning kit which appeared to be a relabeled version of the aFe kit. After cleaning the filter and applying the oil, it seems that my miles per gallon have decreased. Did I over oil the filter? Or did I use the wrong filter? Or is it just me thinking the MPGs decreased?

I cannot comment on AFE products. Have not used them.
I would suspect that the TRD filter is a K&N product.
Perhaps try K&N filter cleaning and oiling products.
Regarding over-oiling. This can be an issue. I’ve used oiled K&N filters since 1988 in all my vehicles and have never had a MAP sensor fouled, as many users have. If fouled it is easily cleaned with Aerosol MAP Sensor cleaner. Do not physically touch the sensor internals. Just blast with the cleaner and air dry.
My maintenance process is as follows;
Remove soiled K&N filter and if a DD temporarily re-installed the paper filter it replaced.
-Using K&N product and following the instructions clean the filter and back flush.
-Allow the filter to dry overnight perhaps outside in a sunny location. Do not use compressed air or a hot blow dryer.
-Next day apply the oil generously into the pleats as per the instructions. Lay out some paper towels and set the oiled filter on them over-night to drain excess oil.
-Next day re-install the K&N and store away the paper filter for the next cleaning process.

Good Luck and enjoy!

The TRD cleaning kit in the picture is a relabeled aFe kit, but there is another TRD cleaning kit with a spray bottle. The issue with this kit is that the oil bottle dispenses too much oil. The instructions say not to overapply and put an even coating across the filter but it's difficult to do so without a spray bottle.

I just started my car today and have a check engine light. I'm guessing it's the MAF sensor because OFT indicated there were no codes. I guess the next step is to clean out the MAF sensor?

Hmmmm. The TRD kit looks identical (re-labelled) to the K&N kit I have in stock.
If I recall, back in the day the kit did come with aerosol oil but has changed over the years.
Now that you have run the car any excess oil will have been pulled from the filter element.
Clean the MAP and you should be set.

Yep, over oiled. I always used the KN kit with spray oil and never had an issue.