thanks... I'm going start watching it more closely, but the problem is I don't put a lot of miles on it... since it's not overheating I may have to take a short road trip and see if it shows more...Most likely the intake is leaking--the TBI's and 1st Gen Vortecs are notorious for it. And often when you shutdown and get out of the truck is when you'll smell it.
Usually the leak is in one of the rear corners of the intake. Sometimes it leaks to the outside, sometimes to the inside. Check your oil for coolant. It may not be leaking enough to show up in the oil, but it ain't good for the motor.........