Ok, major development. I bought this car used, and forgot that the engine was out of an Oldsmobile 88. I'm sorry guys, it totally slipped my mind until I ran across a recall for the fuel pressure regulator on an Oldsmobile 88. It said a backfire could result in damage to the intake. I think this may be it. I'm going to purchase a fpr and install. I'll update here as soon as I install and test.

 

If you get too much fuel in a cylinder, that is called "flooding", it stalls. Also, eventually too much fuel also mixes with the oil, also BAD, and unburnt fuel goes out the exhaust, again, also bad.

You mention a puff of smoke and smells like unburnt fuel. Change the fuel pressure regulator. Also, the fact a vac line from the FPR is filling with gas, again, change the regulator. Otherwise, you will have one of a few problems, fuel mixing in areas it doesn't belong OR as I mentioned, you'll go to start the car, get a LOUD BANG and the upper intake will be destroyed from fuel vapor build up in the UIM exploding when it starts.

As for changing it, the assembly comes apart EASY. It is held in with a single snap ring (C shaped clip, has two little spots for pins to pull the clip together and out). You can use a pic if you don't have snap ring pliers.

I would recommend not starting the car further and immediate oil and filter change after the issue is resolved (just to be safe).

 

Success!! The engine was out of a 1999 Oldsmobile 88. Those cars had a recall on the fuel pressure regulator. I guess mine didn't get changed out before it was put in my car. I replaced it with one from the Zone and it's working fine now. Idled for about 15 minutes and smooth as silk!!

 

Awesome!!! Should be good to go for many more miles!