I have a 91Z TPI 5.7 . once its been running a while,( never hot) shut it down and it smells a bit like gas, or vapor but I cant see a leak. Go to start it, within 20 min and it smokes, mostly looks grey. Is it possible the injectors are leaking into the intake after it shuts down causing this? if it sits over night its fine. thanks, Bruce

 

Test the resistance of your injectors. Should all be around 14-17. You could also pull the vacuum line off of your FPR and check for gas in the line.
It's possible your charcoal canister is plugged as well.
Also, you should test your fuel pressure. See how high it goes and how long it holds.

 

thanks! Ill get on it this weekend!!