Last night my check engine light came on. I got code 25, a lean engine condition. I haven't had the chance to inspect it yet, but it still drives perfect. Will the light reset when the problem is resolved or do I need to reset it by disconnecting the battery? Ant idea what could cause this problem?

 

not sure the problem but the light will go off if you fix it.

 

Just try disconnecting the battery and if it goes away you should be fine. If it comes back you should definitely get it fixed/checked out asap.

 

Make sure your intake pipe from the VaneAirFlowMeter (basically airbox) to the Throttle body has no leaks or tears.
Theoretically there could be a leak in the exhaust before the o2, that's possible.
And then the injectors could be "dirty" and not allowing a good enough mixture.

I used to have Code25, talk about losing mpg...

 

IIRC OBDI toyotas will store the code indefinitely. I think it keeps the light on forever unlike OBDII which will turn the light off after a certain number of ignition cycles that are OK

 

I had same code I fixed vac leaks, intake leaks, maf problems and light was still on for a month but its been coff for a week now but I didn't reset it just cwent off by itself

 

Here are somethings to look and check. I found my engine block ground wire disconnected. I guess owner before forgot to put back on after working on engine. Hope this will help out some of yall in the future.

http://personal.utulsa.edu/~nathan-buchanan/93fsm/engine/85diagnosi.pdf

 

spray some carb cleaner on the injectors and the idle went up. Look like a few bad injector seal.