Since your truck is a 93 it should have a mechanical injection pump?
Check the housing pressure cold advance (HPCA) system, the purpose of this system is to advance ignition timming when cold (up to 80'F) to reduce white smoke and engine missing
To check system;
check for power to small pink wire (could also be a green/black wire, been a long time since i worked on one, anyway it is the smaller wire going to the terminal on pass side of injection pump), key on, engine cold. Should have power until engine reaches approx 80'F
if no power check temp sensor switch rear of pass side head or fuse and wiring
if you have power check operation of HPCA solenoid by unplugging pink wire and running a jumper wire from bat+ to pump terminal when engine is idling hot. You should hear alot more diesel rattle (you are advancing the ignition timing). Solenoid can be replaced without removing ip
Hope this helps and Merry Christmas
Let us know how you make out
Ron
rhsub 99K2500 suburban 6.5 code F,4L80, 4:10, FSD cooler, DSG oil cooler and lines, Dtech FSD, injectors, Isspro egt, trans and boost guages, Bilistein shocks