I have an 89 Camaro RS with a 2.8 V6 700r4 , The check engine light comes on after the car is driven for a while some times stays lit untill I turn the car off and some times goes out after I stop but before shutting the car off , Also if I let the car Idel for a long period (15 - 20 minutes)then put it into drive it will come on. I pulled the code 25 from it but the book that came with the code reader was'nt real clear on what the problem was . Car is running great but I know if there is a code there is a problem and I want to fix it before any real damage is done .
Recent things I have done to the car , Complete rebuild of the Transmission , New ECM , Rebuilt Distributor , New MAF sensor , New TPI sensor , New Water Temp sensor , New Timing Chain and Gears , New Plugs and wires , New Vacumn hoses , New Shocks and Struts

 

code 25 is >>25.High temperature at manifold air temperature sensor OR Vacuum switching valve circuit open or shorted to ground OR High voltage at ATS sensor>>>once you have fixed the prob then dont forget to reset the ecm by disconecting the battery

 

if you can get ahold of a scan tool, see what your air intake temp sensor is reading at, sounds like that may be bad. its the one that screws into the dual snorkel by the drivers side air filter. or just pop one in, theyre only $15 or so. and good call gotfuel, remember to reset the ECM. leave the battery disconnected for a few minutes.

 

Thanks I'll give that a try first , what gotfuel posted I have in my book but was'nt really sure where to start , made this car kinda my hobby , not a mechanic but have been doing pretty good fixing everything wrong just by coming here and this is the last thing that I can find wrong with it .