Engine Performance problem
2005 Chevy Colorado 4 cyl Two Wheel Drive Automatic 82000 miles
truck starts up fine then you go to stop at a light or park when it comes to an idle the truck stalls, then starts right back up, sometimes it stalls again immediately. The engine light is not on. I changed the air filter to a K& N, tuned up the engine, changed the fuel filter and transmission filter change. Advanced Auto couldn't diagnose it, so I took it to a mechanic and the said it wasn't getting any vaccum to the fuel pressure regulator or the throttle position sensor. What is the problem.