Wrong gas 2003 dodge ram 1500 i put my lawn mower gas in my gas tank by mistake i drained the tank put new gas in and the truck only starts for a couple of seconds what do i need to do thanks

Rather than to point out the obvious - you get what you pay for - let me try to help. Vehicles in the scrap yard may sit there anywhere from 1 to 12 months or more, depending upon how part-worthy they are. They get crushed when they are no longer worth the space they take up. Add to the fact that the vehicle may have sat at the owner's home for years before being sent to the yard, and you have no idea how old the gas is that you put in the tank of your Dodge. Fuel tanks will condensate over long periods of time, and there was probably a good bit of water in the gas you obtained. There could also be rust and dirt from inside the tanks as well. And certainly hope that the scrap yard did not mix diesel fuel with the gasoline (it happens!)... That said, the white smoke you mention is a giveaway of water in the combustion chamber. Normally, I would say use dry gas, fill the tank, and drive the water away, but this seems like much more than trace amounts of water. My recommendation would be to have a fuel sample taken from the fuel rail (about a quart) and checked for water. If there is substantial water (I as believe), then you will need to have the tank drained, the fuel filter replaced, and the injectors and fuel lines purged. And next time, pass on the free gas!

NO doubt about it you have a bad fuel pump

This is the year that dodge decided to put the fuel filter in the gas tank instead of inline on the railing. Just either empty the gas tank or make sure that there is hardly and left in it considering it will be heavy. Pull the necessary lines off top of tank and hoses and than take the nuts that hold your straps on the tank off. Remove tank and pull fuel filter.

Inside the fuel tank. Check fuel pressure, should be around 50psi.

gas gauge is broken wire on or near tank.. or its a big tank an could take more to regastir..
dont start, could be fuel pump, or feul pump relay,
brakes, one of the pads prob fell off an is bouncing around in there, happens all the time..

is there a engine light on? take the gas cap of and see if it does better you might have a plugged vent

This code is most likely not related to the problem, it sounds like you may have picked up some contaminated gasoline, maybe has water in it or other like dirt.

buy a new cap!

Pump or relay, or plugged filter. Maybe you got a bad tank of gas.

i hope you drained the ENTIRE fuel system because the feed lines from your tank and the carb float bowl will have contaminated gas as well