So I'm still plugging along on my old 85 f150 and have run across my next snag. When I bought the truck I noticed that the TPS was unplugged from the Carb so I decided to plug it in and see what happened. Well once I plugged it in and drove around the neighborhood the truck ran very rough and would go from running smooth to being sluggish and back and forth. So I though that since it didn't do it when the TPS was unplugged that it had to be the sensor. I picked one up at the parts store and replaced it.... well it's doing the same thing as the other one. So could this be a bad relay or are there other components that work with the TPS?

85 F150
300 Straight 6 carbureted