I have a 2001 Ford Mustang. It is a V6 3.8L automatic. The only problem is. I CANT GET IT TO PASS EMISSIONS! When the slip printed out, the OBD code was P1131, I think, and when I asked a mechanic, he said it was an airflow/O2 sensor. I dont know how to fix it or how much it will cost but its making me very upset that it wont pass. Plus, my check fuel cap light is on. I just bought a brand new one and the light didnt go out. Someone help, PLEASE?
You need to check the fuel pressure on this car as well as make sure gas cap clicks three times when filling with fuel. Also clean teh maf sensor with choke cleaner, make sure there areno leaks in vacuum system or holes in any rubber parts on or attaching to engine. The light won't go out because you need a scan tool to do that. Also before testing after the light is out, change oil and filter, drive car about 15-20 miles on eway where it can get good and warmed up then have it tested.
May, 25, 2012 AT 1:35 AM
P1131 means that the right side (passenger) sees too much air and is letting you know about it. Most people are the slap a o2 sensor on it, but sometimes this can be caused by as simple as a vaccum hose unplugged. Would take actually looking at it to determine the cause on the code. Some I've seen have been intake gasket leaks, some o2 sensors, and one K&N air filter that set this code.
The check fuel cap light is on. IF riding around for a few days don't take it off, you have a major air leak in your gas vapor storage unit (aka Evaporative emissions. Or that vapor you see when fueling your car sometimes)
It has to test the system for it to go off or a scan tool has to take it off for you. But cars usually won't pass inspection unless all the test the car runs itself have passed. So you are definitely looking at a shop to either fix it or spend enough money to pass it for another two years.