My guess is a fuel line rusted out between the transfer case and the body. I had just moved it to the other side of the property, I was sitting by the pond with a line in the water and heard the unmistakable woosh of gas vapors going off.
I kept it down to a dull roar with my 2 f500 water cans until the local fd showed up. Took them 30 minutes and a fair amount of foam to put it out.
Next stop for it is extrication class for the vfd and I will finally be free of that wretched pos..
The drivers side front one has been junk for years but the pass side front is a bavauto replacement.
Can I interest you in a complimentary set of tan Weather tech floor mats?