I have a 1996 Dodge Magnum that fluctuates from 900 to 500 ppm and eventually die

On fuel injected engines this can be caused by the stepping motor which controls low speed engine revs, they need rewiring if faulty, if it's a carby engine it could be a blocked air filter, or dirt blocking a jet in the carby. the fuel tank pick up may be broken, or the fuel pump valves could be faulty. check for a good vacuum on the inlet side of the pump to see if the valve is ok. have you got gas in the tank ?