Hello All! I have a 2001 Mustang GT (4.6) Automatic. I bought it about 2 years ago. Appears to be all stock. I have a vacuum leak. I can't find it. Symptoms: Car starts well and idles perfectly. Drives great for about 20-30 minutes. Then it gradually starts to miss occasionally. After another 10 minutes, it turns into a harder and more steady miss at all speeds and idle. I have started it when cold, drive for about 15 minutes parked at home, then went for another drive 30 minutes...

Help! 2001 GT-I've been trying to find a vacuum leak for months