Q: I was driving my truck and it made this "poof" sound as if something blew. I lost everything--brakes, power steering, and it stalled

Hi, thanks for writing in. It is possible that the "poof" and exhaust smell (rotten gas smell?) both originated from the catalytic converter, and sulfur deposits in the converter. The engine may have backfired through the exhaust, setting off a small combustion event in the catalytic converter - the "poof" you noticed. If you now have a Check Engine light illuminated, which I suspect, have those codes read to guide diagnosis for the poor running you now experience. With the advanced mileage your vehicle has, I suspect your engine may have ’"jumped time", due to a worn timing chain or guides. I recommend having one of our certified automotive technicians from YourMechanic come to your home or office to inspect, diagnose, and repair the issue.