93 4.0 - check engine light comes on only when I put the truck in gear. When I read the code it shows nothing except 000. Thoughts?

 

Welcome to the forum

Doesn't ring any bells for me

I assume an automatic transmission?

Could be loose connection on transmission, i.e. solenoid wire is losing contact with computer so CEL comes on and goes off, it wouldn't set a code if it was momentary

Should be a 3-wire plug in, on drivers side of transmission, in front of shifter, unplug it and look at contacts, plug it back in