1998 Plymouth Voyager how to do it myself

I purchased this vehicle used. after a month i began to feel sputters during accereration. thought it was the transmission. took it to a shop and it turned out not to be. check engine light came on. 02 sensor, bank 1 position 1. replaced. drove 3 days fine with minimal sputter. day 3 after replacement , filled gas tank with super gas. drove 11 miles. parked vehicle. attempted to leave and old problem had returned. vehicle would not accelerate. looked under hood realized egr valve and vac valve was disconnected. i reconnected and drove fine for 2 miles. parked for 30 minutes, problem returned. tried to drive vehicle would not accerlrate above 10mph. had to continuously shut van off then restart. finally van died. i sat for a minute then restarted. stiil acceleration problem. now when it starts it dies after making funny sound under hood and leaves raw gas smell.