I purchased an 06 mustang and it did not have an air filter, so I put one in until I get my CAI. Once in, I got a check engine light and I filled up with gas an now I smell gas. The Code for the check engine light is PO422, which is some kind of fuel issue. I am thinking maybe it had a tune that was set for no air filter and the fuel mixture is too rich. I do not have my tuner yet, is there a way to reset to factory setting with out a tuner. I have read that I can take the negative cable of the battery for 15 min some say 30 not sure. Will this reset the computer to factory settings?

 

All it will do is clear the adaptive learning and trouble codes. You need to get that thing tuned.

 

NO AIR FILTER??? I hate to think what damage has been done...

 

The factory tune is in the hand held tuner that was used on that car, removing battery will not do it. Are you sure you got code p0422? I can't find it in AllData, all I saw was P0420.

 

PO422 from what I can find is the gas cap code or a leak in the vacume or evaporator system.

 

I seem to find "P0422 Main Catalyst Efficiency Below Threshold (Bank 1)" when I hunt around.

 

Here is what I found

A code P0442 most likely means one or more of the following has happened:

A loose or improperly affixed gas cap
A non-conforming gas cap (i.e. not factory/original brand)
A small leak/hole in a fuel vapor hose/tube
Other small leak in EVAP system
Faulty vent o-ring seal

 

+1
Take that stang back and get yo $$ back.
Its life is going to be short lived if it
had no air filter on it for any long period of time...
Does it at least have an oil filter?

 

The light is on for an Evaporative emissions code. Clearing the code will do nothing but turn off the light for a short period of time. If there is a problem, the light WILL come back on. The lack of an air filter can be detrimental over the long haul, but doubtful that anything has happened to it. If you just bought it from a dealer, it's likely they inspected it, saw it needed a filter, and forgot to put one back in before sticking it out on the lot.
And just to keep things straight, a new tune to go along with a CAI, will not eliminate the current MIL problem. Make sure the gas cap is on tight before messing around with anything else.

 

If it were me, I'd install a new OE type air filter, and maybe even a new gas cap. Then, I'd take it to a trusted dealer and have the most current factory tune installed. Even if you plan to install an aftermarket tune, it would be good to have the right factory tune, just in case. Just my $.02 worth.