I have a 1991 RS with a 350 TBI dropped in it. While driving at higher speeds car runs good. At lower speeds occasionally the car will seem to almost die down, and start sputtering. I have new plugs and plug wires. What are some other thing that could cause my problem?

 

Sounds like a vacuum leak. Check intake mating surfaces, vac hoses, power brake booster, etc.

Any trouble codes??