the engine light on my 96 went on the other day. it's been driving fine since but light is still on.
checked the codes and 23 and 25 showed.

any suggestions on what i should check first?

 

I would check for loose wires and if that does not work check the IAT and IAC, I believe they are all one sensor.

 

IAT is located on the intake manifold and is combined with the MAP sensor. Either the sensor is bad, the return wire is grounding out, or the input voltage (5v) is shorting out.

The IAC is located on the TB. Also has a 5v power running to it. Could be the IAC itself being faulty, the IAC being dirty and sticking, or power/ground shorting out.

Since there's a commonality there (5v), that's where I'd start. Follow those wires back to where they splice in and see if anything is out of the ordinary - broken, bare wire, pulled tight, overheating... Can sometimes be a pain to track down. Took me a while to figure out my TPS wiring was rubbing up against the edge of the valve cover and shorting out...

Best of luck!