So, I have a 2002 Pontiac Grand Prix. It has 216,000 miles. Ran fine up until recently. It started stalling out when I would come to a stop or when I started it up and let my foot off the gas. It runs and drives just fine, just not when I come to a stop. I've got to keep one foot on the gas and one foot on the brake. I've got to do this almost the entire time I'm driving it because once it drops back down to idle speed, it stalls out. I've replaced quite a few parts and still no avail. Below is a list of what I can remember that I've replaced. I believe I've replaced almost every sensor under the hood and tried everything that was written online that I could find about the issue. I've swapped ignition module and coil packs from a good known working grand prix and that still didn't fix the issue. I'm at a loss at what may be wrong with it. It's as though there is a vacuum leak somewhere, but I can't find it and smoke or wd-40 on the gaskets does nothing to change idle speed or be able to see any type of vacuum leak sucking in the smoke.
Catalytic Converter
MAF
EGR
Crank Position Sensor
Fuel Pressure Regulator
Intake Manifold
Air Filter
Throttle Position Sensor
Spark plug wires
Solenoid Purge Valve
These are just to name a few. And I've also thought that some of the parts I got may or may not have been bad, but I have access to a parts car and pulled sensors and parts off of it to make sure the new parts and used parts were in good working order. It isn't throwing any codes at the moment and if I hook up a code reader
Anyone have any suggestions?