I've got a '98 ZX2, thing threw a P0113- intake air temp circuit high input. However, I've also lost 5mpg for reasons I am unsure of. I guess if the IAT is telling the computer that it's cold that it would make the scort run rich, but 5mpg!? Is there something I'm missing?

 

See if you can clean the sensor, if not replace it.

 

Most likely your intake air temp sensor is bad. That will mess up your air/fuel ratio. When I changed MAF meters, my new one didn't have the temp. sensor built in like the stock one had. I kept throwing off the CEL. P0113. My car wouldn't dyno tune right bacause of it. When I installed the newsensor on my intake tubeand corrected the air/fuel I found out that I was losing 30 hp from not having it on.