P0125 Toyota -

Question

I have a 98 4 runner 4 cylinder 2.7, it's throwing a po125 code and getting terrible gas mileage. I replaced the thermostat but nothing changed. I checked for a temp sensor but couldn't find one and was told this model doesn't have one or a afr air fuel ratio sensor. Instead I was told it may be bank 1 o2 sensor I would like to be certain of what's causing the issue before I replace anything else. After I clear the code it takes about 20 miles or less before it pops back up. Any help is really appreciated thanks...

Answer 1

HI there,

This vehicle does have an engine coolant temp sensor. This is mounted in the back of the engine on the passenger side. I would change that next, since the truck appears to be running at normal operating temp.