Need a little help here. This is the series of events and the puzzling issue. I had just filled up with 10.5 gallons of 93 (was on 87 for 3 tanks), drove home about 1.5 miles. Parked in the garage and was checking the temps on my AccessPort and decided to reset my ECU and KAM. Started it up and let it idle for 5 minutes then drove again for another 5 miles, came back home. Noticed the idle dipping and getting rough, figured it wasn't enough time for the ECU to learn the idle after reset. I rev it a few times and notice an odd sound coming from the engine, almost like it was under load - then out of nowhere, it sounded like an air compressor suddenly let out all its air. For a split second, I thought my compressor in the garage had sprung a leak until I realized it was coming from my car! The garage quickly filled with a smoke/vapor that had a chemical smell that was very hard to place. Wasn't gas or coolant or oil, that I could tell. Everything on the engine appeared to be fine. I shut it off for about 20 minutes, started it back up and took it for a test drive. Seemed fine and no codes. I was able to replicate it again with the hood up and it appears to be coming from under the car or in the back of the engine when it happens.
Any ideas?
Any ideas?