I have a 92 Camaro RS, I just replaced the engine V8 5.0, and after a drive for a 5 to 10 min, the check engine light up, I checked the code and I have code 12, 21, and 25. Code 12 is normal, means the computer is fine, code 21 is for the Mat Sensor (Manifold Air Temperature) and 25 is Throttle Position Sensor. I replaced both sensor and still doing the same. Can someone help me with this issue pls

 

What do you mean you just replaced the engine? did you do it or did you have it done? I am thinking that if you had is done I would bring it back...if you did it yourself you probably have a manual or something to check.

What was in there before, I mean was the old mill a 5.0 as well?

 

Well let me explained myself better, I bought this car without a engine, last month, I bought a new engine and I put it on (I did it myself), also everything under the hood is new such as: radiator, fans, starter, a/c compressor, alternator, wireset, etc., also I did it myself. The car start normal, drive normal, but like a said before after I drive for 10 min the check engine light comes on, as soon I turn the car off and for a minute or two the light go off. I do not know if this fault was there before, like I said early I bought the car without engine. I already replaced the throttle position sensor and the MAT sensor accordance with the code reader (code 21 and code 25) but still doing the same.