While poking around in my recently purchased 87 3.2 cab, I noticed a four prong connector going to the cat ECU in the right rear of the car. The connector had been disconnected from the harness and was just hanging there. Thinking this couldn't possibly be correct, I reconnected the four prongs. The next time I drove the car ( which was previously running just fine) it seemed a bit sluggish and the "Slow Down" light was intermittently coming on and off. I have read about bad thermocouples and ECU boxes, but is it really just as easy as disconnecting the ECU from the harness to eliminate the problem? I have a new thermocouple laying around that I may install and see what happens, but that is a rather expensive piece if not really needed. All sage advice will be appreciated!