IF the o2 sensor was bad it would still run bad in park?Got real gas smell.The kid i got it from had the o2 sensor unplug he said they told him he didn't need it hook up. That the way I got it that way i plug it back in and it made no diffrent.It should have made a diffrents in way it ran with it plug in and with it not but how would it act?
you should have the O2 sensor plugged in
![Yup yup :yupyup:](https://board.marlincrawler.com/Smileys/marlin/yupyup.gif)
However, not having it plugged in would also affect the truck's running in idle as well as under power.
do you notice any black smoke, is the ignition system upgraded to keep up with the other upgraded parts? it sounds like it might be flooding itself out when you get on the gas.
Still think this is the problem. Check the timing, and lean it out if necessary