Working on a 89' 350 TPI here. Awile ago i was getting a code 43. It seemed to have went away when i put a MSD box in.(The code at least) Anyways the car always wants to backfire a little bit,but only on deceleration,and i have noticed that it has a faint popping noise when it idles,nothing sever but you can still here it. I went and bought a new ESC Module and i thought it was located on the back fire wall near the maf power/burn off and fuel pump relay, but the part they gave me doesn't look anything like the module behind those.. Is it safe to assume that the module i am looking for is located on the distibutor where the 4 prong and 2 prong pigtail lead in from the coil?
I also decided to replace the knock sensor just in case because the distributor is only a few years old and i can't even remember anymore if i put the 350 knock sensor in when i replaced the motor. Any help would be appreciated.

 

ESC module is by the relays you mentioned. Sounds like they sold you an ignition module. Thats the part that goes in the dist.

 

Thanks 92 blue.....you were right......part # i need was ESC 100.......boneheads