So I pulled the codes from my 91 4runner. Says my Air Intake Temp Sensor is not working. I checked the FSM but I could not find anything related to a air intake temp sensor. Can anyone help me out? Is it a big deal? The check engine light has not come on during driving, just gave me the code when I checked for it.

 

What model, year, and engine do you have?

 

On both 22RE and 3VZE, the air temp sensor is in the Air Flow Meter. You might want to check to see if it is gunked up.

 

1991 4runner v6

 

How much does a Air Intake sensor really matter to your rig? What does it exactly do?

 

That was going to be my next question, But I'm trying to chase down a horrid gas mileage issue, so I'd like to rule everything out.

 

Engine temp, air temp and the position of the flap in the AFM all are used to compute the air fuel ratio.

 

I'd suggest to clear the code and see if it returns. The only time I've seen that code is when someone forgot to connect the AFM

 

This can be a huge impact on mileage. The colder the air is, the more fuel you have to add.

I had an issue the other day where the wire to my intake temp sensor died.
My ECU thought it was -40F. It ran rich enough to spit black smoke and partially burned fuel all over the place.. nasty. AFR was off the charts rich.

 

How do I clear codes?