Aaron Bridges

Ok Guys so I have a PI Swapped 96 Mustang GT. It was running fine until I put the new Coolant tube and heater nipple in since then Ive been running lean on the driver side, I have replaced the MAF sensor Replaced UP Stream 02's Injectors are all good Fuel Pressure Is sitting right at 39 PSI I replaced the fuel Filter and Fuel Pump Im stumped here guys I also had a smoke test done to check for Leaks on the Intake absolutely None except for where the sensor connects into the CAI after the MAF Sensor would that cause it to run lean? Any help would be great tired of sinking money into this thing.