so i have a 91 firebird it is a 305 TBI, i had an intake leak so i decided to pull the intake manifold, valve covers and throttle body. i sand blasted and painted the intake and valve covers i also had to remove my distributor. when i put everything back together i timed it the correct way and it ran fine cold but after a while it starts to run way to rich and i noticed the temp gauge wasnt doing anything... my theory is that the computer thinks the engine is still cold when it is warm so it gives it more fuel and spits out black smoke. i replaced the temp sensor on the top of the intake manifold and i still have the same problem, what could it be? maybe a fuse? or a relay? please help! thanks

 

Inspect wiring from temp sensor to ecm. also check for good sensor ground. If you have poor ground it will read cold.

 

If you know someone with a scanner it would only take a few minutes to see what's going on. Otherwise, it's time to get out your volt/ohm meter and start the hunt.