2002 Chevy Venture 192k miles.... recently replace evap purge value, fuel pressure regulator, vapor canister, wires/plugs, water pump, fuel filter and both 02 sensors. Running a lot better than it was before the latest batch of fixes. 3 days later I went to start it and it started right up but... it sounded like the timing was off and the motor was going to explode so I shut it off. Tried again about 3 more times same thing. Waited a couple hours and it quit doing it. Didn't do it again for a couple weeks then it did it again and started right up about 30 mins later. Threw a security code on the message center after it did it the first time. Also idles rough especially in gear. Also have had a random loud bang noise, accompanied by no ability to accel, (temporary) come from the engine bay area while traveling at interstate speeds. This has only happened twice (dont know if problems are connected)

Mass air flow, crank position sensor, bad sensor in key, ignition problem???

HELP!