how many miles? maybe carbon stuck rings??

I thought you said..............
 

The CURSE only applies to BOATS ??, now we find out its JET-SKI's and CARS... And you think your gonna get me on a SKI-LIFT with you ??? I value my skin more than 3,000 bucks CHIEF !! LOL...:D :D

It's Jayl13 that knows the motor.

engine running rich
 

Check the cannister purge valve.I replaced many of them on engines with this condition.It is located in a vacuum line that connects to the front of the carb.

if you are talking about the can that holds vacuum to run the HVAC controls ....... Well there isn't one. The jack ass that installed the headers took it out. would that effect anything other than vent controls?????

Sounds like its in Limp Mode.
Was that OBD-I or Prom style ECM.
Mainfold air pressure sensor?
I can't remeber but does the 93's have a MAF sensor.
If it does, check if any feathers or leaves are in front of the screens.
Or just throw on a 150 shot...that will keep the plugs clean, it did for me!:D

I had similar problems with a 350tpi. I would first try to run a hotter thermostat. Mine started runnig good again when I got the temps back up to 195 to 200 degrees.