Our '93 SSEi could have caught fire too, but not because of the intake/PCM problem, and we were very fortunate - in our case, one of the tranny fluid lines ruptured just as my wife (and baby) arrived at their destination and saw smoke coming fron under the hood.
If it had caught fire, it probably would have burned to the ground.
We now carry fire extinguishers in both of our Bonnies.
The rupture occurred because the plastic hose retainers below the radiator allowed one of the hoses to snap out of place (rearward) and rub on a nearby piece of metal until it cut through the hose.
I used a cable tie to fasten the tranny hoses to the plastic retainer so they can never come loose and do that again.
'99 Bonneville SLE, white, 112,000 miles
'02 Park Avenue Ultra, white diamond pearl, 88,000 miles