I have a 1994 Chevy 1/2 ton extended cab pickup v8, truck is idling for 30 sec check engine lite comes on

Question

After about 30 sec check engine lite comes on, if I rev up engine the light goes off, and I have no problems driving with it, it never comes on then,, just when it idles. Any suggestions?

Answer 1

is it stick or auto?   and sounds? it could be a number of things  

Answer 2

your oxygen sensor is going bad on you.  you might have noticed that it is starting to use a little more gas.  good luck

Answer 3

Take a piece of wire and jump the upper right termials, on the black harness, that is located on the right side of steering column towards the bottom of the dash.  This could also be located right above the emergency brake pedal.  When you put the piece of wire in the terminals make sure the key switch is in the off position.  Once you have those terminals jumped turn the key switch in the on position without trying to start the truck.  Your check engine light should flash a code up of 12 then there will be a brief pause for the computer to diagnose what the problem might be then it will flash up another code which you can call your local parts store and tell them the number of the code and they can tell you what the problem is.