Just swapped the motor out of my car. Put in a good used engine. Starts and drives great. At idle it just has a little hiccup and is a little rough. I also noticed during light throttle cruising it almost feels like it has a slight miss almost like it's starving for air not fuel. Injectors seals are good, did the carb cleaner trick and no difference. Only air leak I can hear is the little white filter mounted on the back of the UIM. It has new plugs, filters, wires. Car sat for a couple years before I got it. Previous kid drove it HARD... The rear tires were smooth and the old clutch was roasted.

Also there is a broke sensor on the housing mounted behind the air pump, hose from the pump goes into this housing. It has two sensors mounted on it, looks like temp sensors. My cats are hollow, do I need to worry about replacing it. -------- found out this is the port air solenoid valve.....

 

Figured it out, amazing what reading the manual does. Adjusted the idle mix screw and reset the idle. Runs smooth and beautiful now. Fixed the cruising issue as well.