Purchased a 93 4wd Carry at a very low price. Engine was pulled, rebuilt and a new 3+1 carb was installed. I redid as many as the vacuum lines as I could figure out with this 3+1 carb thinking it could solve the issue. Coolant flush, refilled at 30 degrees angle with the bleeder open, etc. The short of it is, the truck starts up zero issues. Its been below 45 degrees F every time I've had it running. After 5 to ten minutes at idle, or under 5 minutes driving around slowly in the yard the base idle, if you will, starts to ramp up. It'll creep up until it basically full blown revving as if your foot in on the floor. If you sharply blip the throttle it'll slow down and die within seconds unless you catch it with more throttle before it sputters out. Which it will then rev back to the moon. Shutting it off to cool down is the only solution I've been able to find. Lastly, I've looked up all the information I could and most if not all info is for 2+3 or 3+2 carbs, not the 3+1 like this one. The common carb shown in many articles online is different from the one I have and I am wondering with the part in the square box is/is for if anymore one knows. Picture here Thank you.