On my 88 4 runner, it wouldn't pass smog. After failing i checked engine codes, and code 8 came up and code 25 came up. Looked up code 8 and it says intake air temp sensor, where is that located. Anyone else have any ideas? Should i replace oxygen sensor?

 

intake air temp sensor is in the air-flow meter (on top of the air filter)

check the connectors and terminals for any corrosion or condensation and make sure the terminals are firmly seated in the plugs

 

if you disconnect the plug, disconnect the battery or EFI fuse for a minute or so to clear the code, then go drive and see if the code comes back

 

Well i replaced the oxygen sensor drove it on the freeway, and check engine light came on then went off, checked the codes, and code 5 came up. Not sure what to check now.